As filed with the Securities and Exchange Commission on November 10, 2010 Registration No. 333-        

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT
UNDER THE SECURITIES ACT OF 1933

IRIS INTERNATIONAL, INC.

(Exact name of registrant as specified in its charter)

Delaware
(State of other jurisdiction of
incorporation or organization) 95-2579751
(I.R.S. Employer
Identification No.)

9158 ETON AVENUE
CHATSWORTH, CALIFORNIA 91311
(818) 709-1244
(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

CESAR M. GARCIA
CHIEF EXECUTIVE OFFICER
IRIS INTERNATIONAL, INC.
9158 ETON AVENUE
CHATSWORTH, CALIFORNIA 91311
(818) 709-1244
(Name, address, including zip code, and telephone number, including area code of agent for service)

Copy to:

JOHN J. MCILVERY, ESQ.
STUBBS ALDERTON & MARKILES, LLP
15260 VENTURA BOULEVARD, 20^TH FLOOR
SHERMAN OAKS, CALIFORNIA 91403
(818) 444-4500

Approximate date of commencement of proposed sale to the public: FROM TIME TO TIME AFTER THE EFFECTIVE DATE OF THIS REGISTRATION STATEMENT.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. o

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. þ

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. o

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer o Accelerated filer þ  Non-accelerated filer o
(Do not check if smaller reporting company) Smaller reporting company o

CALCULATION OF REGISTRATION FEE

	Proposed maximum			Amount of
Title of each class of securities to be registered	aggregate offering price(1)(2)			registration fee(3)
Common Stock, par value $0.01 per share	$	(4	)		N/A
Preferred Stock, par value $0.01 per share		(4	)		N/A
Debt Securities		(4	)		N/A
Total:	$	125,000,000.00		$	0

(1)	There are being registered hereunder such indeterminate number of shares of common stock and preferred stock and such indeterminate principal amount of debt securities as may be sold by the registrant from time to time, which together shall have an aggregate initial offering price not to exceed $125,000,000. If any debt securities are issued at an original issue discount, then the offering price of such debt securities shall be in such greater principal amount at maturity as shall result in an aggregate offering price not to exceed $125,000,000, less the aggregate dollar amount of all securities previously issued hereunder. Any securities registered hereunder may be sold separately or as units with the other securities registered hereunder. The proposed maximum offering price per class of security will be determined, from time to time, by the registrant in connection with the issuance by the registrant of the securities registered hereunder. The securities registered hereunder also include such indeterminate number of shares of common stock and preferred stock and amount of debt securities as may be issued upon conversion of or exchange for preferred stock or debt securities that provide for conversion or exchange, upon exercise of warrants or pursuant to the antidilution provisions of any of such securities. In addition, pursuant to Rule 416 under the Securities Act, the shares being registered hereunder include such indeterminate number of shares of common stock and preferred stock as may be issuable with respect to the shares being registered hereunder as a result of stock splits, stock dividends or similar transactions.
(2)	Estimated solely for the purpose of calculating the registration fee in accordance with Rule 457(o) under the Securities Act of 1933, as amended.
(3)	As discussed below, pursuant to Rule 415(a)(6) under the Securities Act, this Registration Statement includes a total of $125,000,000 of unsold securities that had been previously registered and for which the registration fee had been previously paid and will continue to apply to such unsold securities.
(4)	The proposed maximum aggregate offering price per class of security will be determined from time to time by the registrant in connection with the issuance by the registrant of the securities registered hereunder and is not specified as to each class of security pursuant to General Instruction II.D. of Form S-3 under the Securities Act.

     Pursuant to Rule 415(a)(6) under the Securities Act, the securities registered pursuant to this Registration Statement include (i) $125,000,000 of unsold debt securities, common stock, and preferred stock previously registered on the Registration Statement on Form S-3 initially filed with the SEC on November 26, 2007 (Registration No. 333-147618), which we refer to as the prior registration statement. In connection with the registration of such unsold securities on the prior registration statement, IRIS International, Inc. paid a registration fee of $3,838 which will continue to be applied to such unsold securities. Pursuant to Rule 415(a)(6), the offering of the unsold securities registered under the prior registration statement will be deemed terminated as of the date of effectiveness of this Registration Statement.

     The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended (the “Securities Act”) or until this Registration Statement shall become effective on such date as the Securities and Exchange Commission (the “SEC”), acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED NOVEMBER 10, 2010 PROSPECTUS

PROSPECTUS

$125,000,000
Common Stock
Preferred Stock
Debt Securities

     From time to time, we may offer up to $125,000,000 of any combination of the securities described in this prospectus, including common stock, preferred stock or debt securities. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.

     We will provide the specific terms of these offerings and securities in one or more supplements to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before buying any of the securities being offered.

     Our common stock is traded on The Nasdaq Global Market under the symbol “IRIS.” On November 8, 2010, the last reported sale price of our common stock on The Nasdaq Global Market was $9.90. The applicable prospectus supplement will contain information, where applicable, as to any other listing, if any, on The Nasdaq Global Market or any securities market or other exchange of the securities covered by the applicable prospectus supplement.

     Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus.

     This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

     The securities may be sold directly by us to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds that we expect to receive from such sale will also be set forth in a prospectus supplement.

     Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is [•]

TABLE OF CONTENTS

	Page
About This Prospectus		2
Iris International, Inc.		3
Risk Factors		3
Special Note Regarding Forward-Looking Statements		3
The Securities We May Offer		4
Ratios Of Earnings To Fixed Charges And To Combined Fixed Charges And Preferred Dividends		6
Use Of Proceeds		6
Description Of Capital Stock		6
Description Of Debt Securities		11
Legal Ownership Of Securities		17
Plan Of Distribution		21
Legal Matters		22
Experts		22
Where You Can Find More Information		22

     You should rely only on the information that we have provided or incorporated by reference in this prospectus, any applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you. We have not authorized anyone to provide you with different information. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus that we may authorize to be provided to you. You must not rely on any unauthorized information or representation. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate only as of the date on the front of the document and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any related free writing prospectus, or any sale of a security.

ABOUT THIS PROSPECTUS

     This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission utilizing a “shelf” registration process. Under this shelf registration process, we may offer shares of our common stock and preferred stock and various series of debt securities in one or more offerings, up to a total dollar amount of $125,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of those securities. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add, update or change in the prospectus supplement (and in any related free writing prospectus that we may authorize to be provided to you) any of the information contained in this prospectus or in the documents that we have incorporated by reference into this prospectus. We urge you to carefully read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Where You Can Find More Information,” before buying any of the securities being offered. THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

     This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find More Information.”

          Unless the context otherwise requires, the terms “we,” “our,” “us,” “our company,” and “IRIS” refer to IRIS International, Inc. and its subsidiaries.

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IRIS INTERNATIONAL, INC.

     IRIS International, Inc. is engaged in the design, development, manufacturing and marketing of patented and proprietary image-based in vitro diagnostic systems. Our products leverage our strengths in flow imaging technology, particle recognition and automation to bring efficiency to hospital and commercial laboratories. The initial applications for this technology have been in the urinalysis market and we are a leading worldwide provider of automated urine microscopy systems, with over 2,900 instruments sold in over 50 countries. In this market, we also provide integrated solutions comprising urine microscopy and urine chemistry products as well as consumable supplies, system support services and sample preparation products. We intend to expand into related market segments that can clearly benefit from automated morphology solutions, including developing the analysis of other body fluids such as hematology applications.

     In addition, we have an active research and development program in molecular diagnostics based on our Nucleic Acid Detection Immunoassay, or NADiA®, technology platform, which we are developing for various applications in oncology and infectious disease. The first NADiA product pending 510(k) clearance is a prostate cancer prognostic diagnostic test, called NADiA®ProsVue™, designed to identify patients at low risk of cancer recurrence, post-radical prostatectomy.

     In July 2010, we acquired a high complexity CLIA-certified molecular pathology laboratory offering differentiated, high value molecular diagnostic services in the rapidly growing field of personalized medicine. The laboratory is expected to accelerate the development efforts of NADiA’s product pipeline and provide for a direct commercial channel for our NADiA ® products, beginning with NADiA®ProsVue™.

     .We were incorporated under the laws of the state of Delaware on June 9, 1987. Our principal executive offices are located at 9158 Eton Avenue, Chatsworth, California 91311, and our telephone number is (818) 527-7000. Our website address is www.proiris.com. The information on our website is not a part of this prospectus.

RISK FACTORS

     Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

     This prospectus and the documents incorporated by reference contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward-looking statements. These forward-looking statements include, but are not limited to, those concerning the following:

• our expectations regarding our future operating results or financial performance;

• our intentions, expectations and beliefs regarding anticipated growth, market penetration and trends in our business;

• the timing and success of our research and development efforts and regulatory submissions;

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• our ability to commercialize and achieve market acceptance of new products that we may develop;

• our ability to successfully acquire and integrate other businesses into our operations; and

• our ability to protect our intellectual property and operate our business without infringing upon the intellectual property rights of others.

     In some cases, you can identify forward-looking statements by terms such as “anticipates,” “believes”, “could”, “estimates”, “expects”, “intends”, “may”, “plans”, “potential”, “predicts”, “projects”, “should”, “will”, “would” as well as similar expressions. Forward-looking statements reflect our current views with respect to future events, are based on assumptions and are subject to risks, uncertainties and other important factors. We discuss many of these risks, uncertainties and other important factors in greater detail under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and in our most recent annual report on Form 10-K and in our most recent quarterly report on Form 10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. Given these risks, uncertainties and other important factors, you should not place undue reliance on these forward-looking statements. Also, these forward-looking statements represent our estimates and assumptions only as of the date such forward-looking statements are made. Except as required by law, we assume no obligation to update any forward-looking statements publicly, or to reflect facts and circumstances after the date of this prospectus. Before deciding to purchase our securities, you should carefully read both this prospectus, the applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Where You Can Find More Information,” completely and with the understanding that our actual future results may be materially different from what we expect.

THE SECURITIES WE MAY OFFER

     We may offer shares of our common stock and preferred stock, and various series of debt securities, with a total value of up to $125,000,000 from time to time under this prospectus at prices and on terms to be determined by market conditions at the time of any offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

• designation or classification;

• aggregate principal amount or aggregate offering price;

• maturity, if applicable;

• original issue discount, if any;

• rates and times of payment of interest or dividends, if any;

• redemption, conversion, exercise, exchange or sinking fund terms, if any;

• ranking;

• restrictive covenants, if any;

• voting or other rights, if any;

• conversion prices, if any; and

• important United States federal income tax considerations.

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     The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

     THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

     We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents or underwriters, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents or underwriters, we will include in the applicable prospectus supplement:

• the names of those agents or underwriters;

• applicable fees, discounts and commissions to be paid to them;

• details regarding over-allotment options, if any; and

• the net proceeds to us.

     Common Stock. We may issue shares of our common stock from time to time. The holders of common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders and do not have cumulative voting rights. Subject to preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably only those dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock.

     Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Our board of directors will determine the designations, powers, preferences and rights of the preferred stock, as well as the qualifications, limitations or restrictions thereon, including dividend rights, conversion rights, preemptive rights, voting rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series. Convertible preferred stock will be convertible into our common stock or exchangeable for our other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates. We will fix the designations, powers, preferences and rights of the preferred stock of each series, as well as the qualifications, limitations or restrictions thereon, in the certificate of designation relating to that series.

     If we sell any series of preferred stock under this prospectus, we will fix the designations, powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereon, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

     Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior debt or as senior convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. Convertible debt securities will be convertible into or exchangeable

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for our common stock or our other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

     The debt securities will be issued under one or more indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the forms of indentures and forms of debt securities containing the terms of the debt securities being offered.

RATIOS OF EARNINGS TO FIXED CHARGES

     The following table sets forth our ratio of earnings to fixed charges for the periods indicated.

For the Nine

Months Ended

September 30,

For the Years Ended December 31,

2010

2009

2008

2007

2006

2005

Ratio of earnings to fixed charges

7.3x

13.7x

23.0x

20.7x

5.5x

33.8x

     For purposes of calculating these ratios, earnings is the amount resulting from (1) adding (a) pretax income from continuing operations before adjustment for minority interests in consolidated subsidiaries or income or loss from equity investees, (b) fixed charges, (c) amortization of capitalized interest, (d) distributed income of equity investees and (e) our share of pre-tax losses of equity investees for which charges arising from guarantees are included in fixed charges and (2) subtracting (i) interest capitalized, (ii) preference security dividend requirements of consolidated subsidiaries and (iii) the noncontrolling interest in pre-tax income of subsidiaries that have not incurred fixed charges. Fixed charges is the sum of (w) interest expensed and capitalized, (x) amortized premiums, discounts and capitalized expenses related to indebtedness, (y) an estimate of the interest within rental expense and (z) preference security dividend requirements of our consolidated subsidiaries.

     In addition, for the periods presented above, we did not have outstanding preferred securities and therefore were not required to pay any preferred security dividends. As a result, our ratios of earnings to combined fixed charges and preference dividends are identical to the ratios presented in the table above.

USE OF PROCEEDS

     Except as described in any prospectus supplement or in any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the net proceeds from the sale of the securities offered hereby for working capital, capital expenditures and other general corporate purposes, and for product development. We also may use a portion of the proceeds to finance potential acquisitions and investments in companies or products that are complementary to our business if and when suitable opportunities arise; however, we currently have no commitments or agreements with respect to any such transactions. Pending these uses, we expect to invest the net proceeds in short-term, investment-grade securities.

DESCRIPTION OF CAPITAL STOCK

     Our authorized capital stock consists of 50,000,000 shares of common stock, $0.01 par value, and 3,000,000 shares of preferred stock, $0.01 par value. As of October 26, 2010, there were:

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• 18,138,216 shares of common stock outstanding;

• no shares of preferred stock outstanding; and

• 250,000 shares of preferred stock designated as Series A Preferred Stock, none of which were outstanding.

     The following summary description of our capital stock is based on the provisions of our certificate of incorporation and bylaws, our stockholder rights plan and the applicable provisions of the Delaware General Corporation Law. This information is qualified entirely by reference to the applicable provisions of our certificate of incorporation, bylaws, stockholder rights plan and the Delaware General Corporation Law. For information on how to obtain copies of our certificate of incorporation, bylaws and stockholder rights plan, which are exhibits to the registration statement of which this prospectus is a part, see “Where You Can Find More Information.”

Common Stock

     The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders. Our stockholders do not have cumulative voting rights in the election of directors. Subject to preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably only those dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive or other subscription or conversion rights. There are no redemption or sinking fund provisions applicable to our common stock. Shares of our common stock outstanding, and to be issued, are, and will be, fully paid and non-assessable.

Preferred Stock

     Pursuant to our certificate of incorporation, our board of directors has the authority, without further action by the stockholders (unless such stockholder action is required by applicable law or the rules of The Nasdaq Stock Market), to designate and issue up to 3,000,000 shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, to fix the designations, powers, preferences and rights of the shares of each wholly unissued series, and any qualifications, limitations or restrictions thereon, and to increase or decrease the number of shares of any such series, but not below the number of shares of such series then outstanding. Shares of our preferred stock, if issued, will be, fully paid and non-assessable.

     We will fix the designations, powers, preferences and rights of the preferred stock of each series, as well as the qualifications, limitations or restrictions thereon, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of that series of preferred stock. This description will include:

• the title and stated value;

• the number of shares we are offering;

• the liquidation preference per share;

• the purchase price;

• the dividend rate, period and payment date and method of calculation for dividends;

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• whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

• the procedures for any auction and remarketing, if any;

• the provisions for a sinking fund, if any;

• the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

• any listing of the preferred stock on any securities exchange or market;

• whether the preferred stock will be convertible into our common stock, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;

• whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange price, or how it will be calculated, and the exchange period;

• voting rights, if any, of the preferred stock;

• preemptive rights, if any;

• restrictions on transfer, sale or other assignment, if any;

• whether interests in the preferred stock will be represented by depositary shares;

• a discussion of any material United States federal income tax considerations applicable to the preferred stock;

• the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

• any limitations on the issuance of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

• any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.

     The General Corporation Law of the State of Delaware, or DGCL, the state of our incorporation, provides that the holders of preferred stock will have the right to vote separately as a class (or, in some cases, as a series) on an amendment to our certificate of incorporation if the amendment would change the par value or, unless the certificate of incorporation provided otherwise, the number of authorized shares of the class or change the powers, preferences or special rights of the class or series so as to adversely affect the class or series, as the case may be. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

     Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of our common stock. Preferred stock could be issued quickly with terms designed to delay or prevent a change in control of our company or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of our common stock.

Series A Preferred Stock

     Our board of directors has designated 250,000 shares of our preferred stock as Series A Preferred Stock. The Series A Preferred Stock is purchasable upon exercise of the rights pursuant to the terms of our stockholder rights plan. For more information on our stockholder rights plan, please see “Description

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of Capital Stock — Stockholders Rights Plan.” These shares or the holders of these shares, as applicable, are:

• not redeemable;

• entitled, subject to the rights of the holders of any shares of preferred stock to receive preferential dividends and in preference to the holders of our common stock and any other junior stock, to receive, when and if declared by our board of directors, quarterly dividends in an amount per share equal to the greater of $1.00 or 1,000 times (subject to adjustment) the aggregate per share amount of all non-cash dividends or other distributions declared on our common stock since the previous quarterly payment or, in the case of the first quarterly payment, since the first issuance of our Series A Preferred Stock;

• entitled upon liquidation, before any payment may be made to holders of our common stock or and any other junior stock, to receive a minimum preferential payment per share in an amount equal to the accrued and unpaid dividends and distributions on the shares of Series A Preferred Stock thereon, whether or not declared, to the date of such payment, plus an amount equal to the greater of $0.01 per whole share or 1,000 times the aggregate amount to be distributed per share to holders of our common stock;

• entitled to 1,000 votes (subject to adjustment) per share of Series A Preferred Stock, voting together with our common stock; and

• entitled, in the event of a merger, consolidation or other transaction in which outstanding shares of our common stock are converted or exchanged, to receive 1,000 times (subject to adjustment) the amount received per share of our common stock.

Equity Compensation Plans

     As of November 5, 2010, there were 3,604,111 shares of common stock reserved for issuance under our equity compensation plans, or upon exercise of outstanding options. Of this number, 2,814,850 shares were reserved for issuance upon exercise of outstanding options that were previously granted under our equity compensation plans and 789,261 shares were reserved for issuance pursuant to awards that may be granted in the future under our equity compensation plans.

Section 203 of the General Corporation Law of the State of Delaware

     We are subject to Section 203 of DGCL, which prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, with the following exceptions:

• before such date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested holder;

• upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding (but not the outstanding voting stock owned by the interested stockholder) those shares owned (i) by persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

• on or after such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of the stockholders, and not by written consent,

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by the affirmative vote of at least 66 2/3% of the outstanding voting stock that is not owned by the interested stockholder.

     In general, Section 203 defines business combination to include the following:

• any merger or consolidation involving the corporation and the interested stockholder;

• any sale, lease, transfer, pledge or other disposition of 10% or more of the assets of the corporation to or with the interested stockholder;

• subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

• any transaction involving the corporation that has the effect of increasing the proportionate share of the stock or any class or series of the corporation beneficially owned by the interested stockholder; or

• the receipt by the interested stockholder of the benefit of any loss, advances, guarantees, pledges or other financial benefits by or through the corporation.

     In general, Section 203 defines interested stockholder as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation or any entity or person affiliated with or controlling or controlled by such entity or person.

Stockholder Rights Plan

     We have adopted a stockholder rights plan. Under our stockholder rights plan, each share of our common stock has associated with it one preferred share purchase right. Each right entitles its holder to purchase, under the circumstances provided for in our stockholder rights plan, one one-thousandth of a share of Series A Preferred Stock at an initial purchase price equal to $100.00, subject to adjustment under certain circumstances. Until a “distribution date” occurs, the rights:

• are not exercisable;

• are evidenced by the same certificate that represents the shares with which the rights are associated; and

• trade together with those shares.

     Following a “distribution date,” the rights would become exercisable and we would issue separate certificates representing the rights, which would trade separately from the shares of our common stock. A “distribution date” would occur upon the earlier of:

• first day of a public announcement that a person has become an “acquiring person”; or

• the tenth day after public announcement of a tender or exchange offer the consummation of which would result in the person becoming an “acquiring person”.

     Under our stockholder rights plan, a person becomes an “acquiring person” if the person, alone or together with a group, acquires beneficial ownership of 20% or more of the outstanding shares of our common stock. However, an acquiring person would not include us, any of our subsidiaries, or any of our or our subsidiaries’ employee benefit plans or any person or entity organized, appointed or established by us or any subsidiary of us for, or pursuant to, the terms of such employee benefit plan. In addition, acquisitions directly from us or made with the prior approval of our board of directors and tender or exchange offers meeting certain criteria will likewise not trigger the distribution of the rights under our stockholder rights plan.

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     In the event that any person becomes an acquiring person, each right will give the holder (other than the “acquiring person”, its affiliates and transferees) the right to purchase from us, for $100, that number of one one-thousandth of a share of Series A Preferred Stock (or, in certain circumstances, common stock, cash, property or other securities of ours) having a market value of $200. All rights that are beneficially owned by any “acquiring person” will be null and void.

     At any time before a person becomes an acquiring person, our board of directors may redeem all of the rights at a redemption price of $0.001 per right. On the redemption date, the rights will expire and the only entitlement of the holders of rights will be to receive the redemption price.

     At any time before a person becomes an acquiring person, our board of directors may amend any provision in the rights plan without the consent of the holders of the rights. After a person becomes an acquiring person, our board of directors may not amend our stockholder rights plan in a manner which adversely affects the interests of the holders of rights In general, the rights will expire at the close of business on September 24, 2020, unless earlier redeemed or exchanged by us.

     The exercise of the rights under our stockholder rights plan would cause substantial dilution to a person attempting to acquire us on terms not approved by our board of directors, and therefore would significantly increase the price that such person would have to pay to complete the acquisition. Our stockholder rights plan may deter a potential acquisition or tender offer.

Transfer Agent and Registrar

     The transfer agent and registrar for our common stock is Continental Stock Transfer & Trust Company, 17 Battery Place, New York, NY 10004-1123. The transfer agent for any series of preferred stock that we may offer under this prospectus will be named and described in the prospectus supplement for that series.

DESCRIPTION OF DEBT SECURITIES

     We may issue debt securities, in one or more series, as either senior or as senior or convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indentures, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

     We will issue the senior debt securities under the senior indenture that we will enter into with the trustee named in the senior indenture. We have filed a form of senior indenture as an exhibit to this registration statement, which includes this prospectus. The indentures will be qualified under the Trust Indenture Act of 1939. We use the term “debenture trustee” to refer to the trustee under the senior indenture. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, supplemental indentures and forms of debt securities containing the terms of the debt securities being offered.

     The following summaries of material provisions of the senior debt securities and the indentures are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indentures that contains the terms of the debt securities.

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General

     We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

• the title;

• the principal amount being offered, and if a series, the total amount authorized and the total amount outstanding;

• any limit on the amount that may be issued;

• whether or not we will issue the series of debt securities in global form, the terms and who the depositary will be;

• the maturity date;

• whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a United States person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

• the annual interest rate, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

• whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

• the terms of the subordination of any series of subordinated debt;

• the place where payments will be payable;

• restrictions on transfer, sale or other assignment, if any;

• our right, if any, to defer payment of interest and the maximum length of any such deferral period;

• the date, if any, after which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

• the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

• whether the indenture will restrict our ability and/or the ability of our subsidiaries to:

• incur additional indebtedness;

• issue additional securities;

• create liens;

• pay dividends and make distributions in respect of our capital stock and the capital stock of our subsidiaries;

• redeem capital stock;

• place restrictions on our subsidiaries’ ability to pay dividends, make distributions or transfer assets;

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• make investments or other restricted payments;

• sell or otherwise dispose of assets;

• enter into sale-leaseback transactions;

• engage in transactions with stockholders and affiliates;

• issue or sell stock of our subsidiaries; or

• effect a consolidation or merger.

• whether the indenture will require us to maintain any interest coverage, fixed charge, cash flow-based, asset-based or other financial ratios;

• a discussion of any material United States federal income tax considerations applicable to the debt securities;

• information describing any book-entry features;

• provisions for a sinking fund purchase or other analogous fund, if any;

• the applicability of the provisions in the indenture on discharge;

• whether the debt securities are to be offered at a price such that they will be deemed to be offered at an “original issue discount” as defined in paragraph (a) of Section 1273 of the Internal Revenue Code;

• the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

• the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars; and

• any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, including any additional events of default or covenants provided with respect to the debt securities, and any terms that may be required by us or advisable under applicable laws or regulations.

Conversion or Exchange Rights

     We will set forth in the prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

     The indentures will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of all or substantially all of our assets. However, any successor to or acquirer of such assets must assume all of our obligations under the indentures or the debt securities, as appropriate. If the debt securities are convertible into or exchangeable for our other securities or securities of other entities, the person with whom we consolidate or merge or to whom we sell all of our property must make provisions for the conversion of the debt securities into securities that the holders of the debt securities would have received if they had converted the debt securities before the consolidation, merger or sale.

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Events of Default Under the Indenture

     Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

• if we fail to pay interest when due and payable and our failure continues for 90 days and the time for payment has not been extended or deferred;

• if we fail to pay the principal, premium or sinking fund payment, if any, when due and payable and the time for payment has not been extended or delayed;

• if we fail to observe or perform any other covenant contained in the debt securities or the indentures, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive notice from the debenture trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

• if specified events of bankruptcy, insolvency or reorganization occur.

     If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the debenture trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the debenture trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the debenture trustee or any holder.

     The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

     Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the debenture trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the debenture trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the debenture trustee, or exercising any trust or power conferred on the debenture trustee, with respect to the debt securities of that series, provided that:

• the direction so given by the holder is not in conflict with any law or the applicable indenture; and

• subject to its duties under the Trust Indenture Act of 1939, the debenture trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

     A holder of the debt securities of any series will have the right to institute a proceeding under the indentures or to appoint a receiver or trustee, or to seek other remedies only if:

• the holder has given written notice to the debenture trustee of a continuing event of default with respect to that series;

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• the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request, and such holders have offered reasonable indemnity to the debenture trustee to institute the proceeding as trustee; and

• the debenture trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

     These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

     We will periodically file statements with the debenture trustee regarding our compliance with specified covenants in the indentures.

Modification of Indenture; Waiver

     We and the debenture trustee may change an indenture without the consent of any holders with respect to specific matters:

• to fix any ambiguity, defect or inconsistency in the indenture;

• to comply with the provisions described above under “Description of Debt Securities — Consolidation, Merger or Sale;”

• to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act of 1939;

• to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

• to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided under “Description of Debt Securities — General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

• to evidence and provide for the acceptance of appointment hereunder by a successor trustee;

• to provide for uncertificated debt securities in addition to or in place of certificated debt securities and to make all appropriate changes for such purpose;

• to add to our covenants such new covenants, restrictions, conditions or provisions for the protection of the holders, and to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default; or

• to change anything that does not materially adversely affect the interests of any holder of debt securities of any series.

     In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the debenture trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the debenture trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

• extending the fixed maturity of the series of debt securities;

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• reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any debt securities; or

• reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

Discharge

     Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

• register the transfer or exchange of debt securities of the series;

• replace stolen, lost or mutilated debt securities of the series;

• maintain paying agencies;

• hold monies for payment in trust;

• recover excess money held by the debenture trustee;

• compensate and indemnify the debenture trustee; and

• appoint any successor trustee.

     In order to exercise our rights to be discharged, we must deposit with the debenture trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

     We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company or another depositary named by us and identified in a prospectus supplement with respect to that series. See “Legal Ownership of Securities” for a further description of the terms relating to any book-entry securities.

     At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of any series of debt securities can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

     Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

     We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

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     If we elect to redeem the debt securities of any series, we will not be required to:

• issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

• register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Debenture Trustee

     The debenture trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the debenture trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the debenture trustee is under no obligation to exercise any of the powers given it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

     Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

     We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the debenture trustee in New York City as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

     All money we pay to a paying agent or the debenture trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

     The indentures and the debt securities will be governed by and construed in accordance with the laws of the State of California, except to the extent that the Trust Indenture Act of 1939 is applicable.

LEGAL OWNERSHIP OF SECURITIES

     We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect

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holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

     We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

     Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

     As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not holders, of the securities.

Street Name Holders

     We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

     For securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

     Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

     For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the

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consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the holders.

Special Considerations For Indirect Holders

     If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:

• how it handles securities payments and notices;

• whether it imposes fees or charges;

• how it would handle a request for the holders’ consent, if ever required;

• whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

• how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

• if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

     A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

     Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, New York, New York, known as DTC, will be the depositary for all securities issued in book-entry form.

     A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a holder of the security, but only an indirect holder of a beneficial interest in the global security.

     If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations For Global Securities

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     The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

     If securities are issued only in the form of a global security, an investor should be aware of the following:

• an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

• an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

• an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

• an investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

• the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security;

• we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security, nor do we or any applicable trustee supervise the depositary in any way;

• the depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

• financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

     There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

     In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

     Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

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• if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

• if we notify any applicable trustee that we wish to terminate that global security; or

• if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

     The prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

     We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

• at a fixed price or prices, which may be changed;

• at market prices prevailing at the time of sale;

• at prices related to such prevailing market prices; or

• at negotiated prices.

     Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement.

     If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

     We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

     We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

     We may provide agents and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or

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underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

     All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

     Any underwriter may engage in over-allotment, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum price. Syndicate-covering or other short-covering transactions involve purchases of the securities, either through exercise of the over-allotment option or in the open market after the distribution is completed, to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

     Any underwriters that are qualified market makers on The Nasdaq Global Market may engage in passive market making transactions in the common stock on The Nasdaq Global Market in accordance with Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the common stock. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

     In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

LEGAL MATTERS

     The validity of the securities being offered hereby will be passed upon for us by Stubbs Alderton & Markiles, LLP, 15260 Ventura Boulevard, 20^th Floor, Sherman Oaks, California 91403.

EXPERTS

     The consolidated financial statements and schedule as of December 31, 2009 and 2008 and for each of the three years in the period ended December 31, 2009 and our report on the effectiveness of internal control over financial reporting as of December 31, 2009 incorporated by reference in this Prospectus have been so incorporated in reliance on the reports of BDO USA, LLP., an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

     We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any document we file at the SEC’s Public Reference Room at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the public reference room. The SEC maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC, including IRIS International, Inc. The SEC’s Internet site can be found at www.sec.gov.

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     The SEC allows us to incorporate by reference the information we file with it, which means that we can disclose important information to you by referring you to another document that we have filed separately with the SEC. You should read the information incorporated by reference because it is an important part of this prospectus. We incorporate by reference the following information or documents that we have filed with the SEC (Commission File No. 001-11181):

• our Annual Report on Form 10-K for our fiscal year ended December 31, 2009 (filed on March 16, 2010);

• our Quarterly Reports on Form 10-Q for the fiscal quarter ended March 31, 2010 (filed on May 7, 2010), for the fiscal quarter ended June 30, 2010 (filed on August 6, 2010), and for the fiscal quarter ended September 30, 2010 (filed on November 9, 2010); and

• our Current Reports on Form 8-K, dated January 4, 2010 (filed on January 6, 2010); dated January 13, 2010 (filed on January 20, 2010); dated March 1, 2010 (filed on March 1, 2010); dated May 3, 2010 (filed on May 3, 2010); dated May 10, 2010 (filed on May 14, 2010); dated May 14, 2010 (filed on May 20, 2010); dated June 9, 2010 (filed on June 15, 2010); dated July 27, 2010 (filed on July 27, 2010); dated July 28, 2010 (filed on July 28, 2010); dated July 26, 2010 (filed on July 30, 2010, as amended on October 12, 2010); dated July 29, 2010 (filed on August 3, 2010); dated August 18, 2010 (filed on August 19, 2010); dated August 31, 2010 (filed on September 2, 2010); dated September 1, 2010 (filed on September 7, 2010); dated September 24, 2010 (filed on September 29, 2010); dated October 11, 2010 (filed on October 13, 2010); and dated October 28, 2010 (filed on October 28, 2010);

• the description of our common stock contained in our registration statement on Form 8-A, as filed with the SEC on April 6, 2004; and

• the description of Series A Preferred Stock contained in our registration statement on Form 8-A, as filed with the SEC on September 29, 2010.

     Any information in any of the foregoing documents will automatically be deemed to be modified or superseded to the extent that information in this prospectus or in a later filed document that is incorporated or deemed to be incorporated herein by reference modifies or replaces such information.

     We also incorporate by reference any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including all such reports filed after the date of the initial registration statement and prior to effectiveness of the registration statement, until we file a post-effective amendment that indicates the termination of the offering of the securities made by this prospectus. Information in such future filings updates and supplements the information provided in this prospectus. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements.

     We have filed with the SEC a registration statement on Form S-3 under the Securities Act with respect to the securities offered with this prospectus. This prospectus does not contain all of the information in the registration statement, parts of which we have omitted, as allowed under the rules and regulations of the SEC. You should refer to the registration statement for further information with respect to us and our securities. Statements contained in this prospectus as to the contents of any contract or other document are not necessarily complete and, in each instance, we refer you to the copy of each contract or document filed as an exhibit to the registration statement. Copies of the registration statement, including

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exhibits, may be obtained without charge at the website maintained by the SEC at www.sec.gov, or may be inspected without charge at the SEC’s principal office in Washington, D.C., and you may obtain copies from that office upon payment of the fees prescribed by the SEC.

     We will furnish without charge to each person to whom a copy of this prospectus is delivered, upon written or oral request, a copy of the documents that have been incorporated by reference into this prospectus, including exhibits to these documents. You should direct any requests for copies to: Investor Relations, IRIS International, Inc., 9158 Eton Avenue, Chatsworth, California 91311; telephone number (818) 709-1244.

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PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

     The following table sets forth the estimated costs and expenses, other than the underwriting discounts and commissions payable by the Registrant in connection with the offering of the securities being registered. All amounts are estimates, except the SEC registration fee.

SEC registration fee	$	0
Accounting fees and expenses	$	5,000
Legal fees and expenses	$	10,000
Transfer Agent fees and expenses	$	5,000
Printing and related fees	$	5,000
Miscellaneous	$	2,500
Total	$	27,500

ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 145 of the Delaware General Corporation Law provides that a corporation may indemnify directors and officers as well as other employees and individuals against expenses, including attorneys’ fees, judgments, fines and amounts paid in settlement in connection with specified actions, suits or proceedings, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation or a derivative action), if they acted in good faith and in a manner they reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal action or proceedings, had no reasonable cause to believe their conduct was unlawful.

     A similar standard is applicable in the case of derivative actions, except that indemnification only extends to expenses (including attorneys’ fees) actually and reasonably incurred in connection with the defense or settlement of such action, and the statute requires court approval before there can be any indemnification where the person seeking indemnification has been found liable to the corporation. The statute provides that it is not exclusive of other indemnification that may be granted by a corporation’s Certificate of Incorporation, Bylaws, disinterested director vote, stockholder vote, agreement or otherwise.

     As permitted by Section 145 of the Delaware General Corporation Law, Article VIII of our Certificate of Incorporation, as amended, provides:

“The corporation shall to the fullest extent permitted by Section 145 of the Delaware General Corporation Law indemnify all persons whom it may indemnify pursuant thereto.”

     The Registrant’s Bylaws provide for indemnification of officers and directors to the fullest extent permitted by Delaware law. In addition, the Registrant has, and intends in the future to enter into, agreements to provide indemnification for directors and officers in addition to that provided for in the Bylaws.

     The Registrant maintains insurance on behalf of any person who is a director or officer against any loss arising from any claim asserted against any of them and expense incurred by any of them in any capacity, subject to certain exclusions.

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ITEM 16. EXHIBITS.

Exhibit		Incorporated by Reference						Filed
Number	Description	Form	File Number	Exhibit			Filing Date	Herewith
1.1	Form of Underwriting Agreement								(1)
4.1(a)	Certificate of Incorporation, filed June 9, 1987	8-K	001-11181		3.1	(a)	September 29, 2010		—
4.1(b)	Certificate of Amendment of Certificate of Incorporation, filed July 9, 1993	8-K	001-11181		3.1	(b)	September 29, 2010		—
4.1(c)	Certificate of Amendment of Certificate of Incorporation, filed June 6, 2001	8-K	001-11181		3.1	(c)	September 29, 2010		—
4.1(d)	Certificate of Ownership and Merger, filed November 26, 2003	8-K	001-11181		3.1	(d)	September 29, 2010		—
4.1(e)	Certificate of Correction of Certificate of Ownership and Merger, filed December 11, 2003	8-K	001-11181		3.1	(e)	September 29, 2010		—
4.1(f)	Certificate of Designation of Rights, Preferences and Privileges of Series A Preferred Stock, filed September 27, 2010	8-K	001-11181		3.1	(f)	September 29, 2010		—
4.2	Amended and Restated Bylaws.	8-K	001-11181		3.2		July 18, 2007		—
4.3	Rights Agreement, dated as of September 24, 2010, between the Registrant and Continental Stock Transfer & Trust Company, as Rights Agent, including the Certificate of Designation of Rights, Preferences and Privileges of Series A Preferred Stock, the Form of Rights Certificate, and the Summary of Rights to Purchase Preferred Stock, attached thereto as Exhibits A, B and C, respectively.	8-K	001-11181		4.1		September 29, 2010		—
4.4	Specimen of Common Stock certificate	S-3	333-147618		4.2		November 26, 2007		—
4.5	Specimen Preferred Stock certificate of the Registrant and Form of Certificate of Designation of Preferred Stock of the Registrant								(1	)
4.6	Form of Senior Debt Indenture, between the Registrant and one or more trustees to be named								*
4.7	Form of Senior Note								(1	)
48	Form of Preferred Stock Certificate								(1	)
5.1	Opinion of Stubbs Alderton & Markiles, LLP								*
12.1	Statement of Computation of Ratios of Earning to Fixed Charges								*
23.1	Consent of Stubbs Alderton & Markiles, LLP (included in Exhibit 5.1)								*
23.2	Consent of BDO USA, LLP, independent registered public accounting firm								*
24.1	Power of Attorney (included on signature page)								*

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Exhibit		Incorporated by Reference				Filed
Number	Description	Form	File Number	Exhibit	Filing Date	Herewith
25.1	Statement of Eligibility of Trustee under the Senior Debt Indenture						(1	)

(1) To be filed by amendment or as an exhibit to a document to be incorporated or deemed to be incorporated by reference in this registration statement, including a Current Report on Form 8-K.

ITEM 17. UNDERTAKINGS.

     The undersigned Registrant hereby undertakes:

     (1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

     (i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

     (ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in the volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

     (iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (1)(i), (1)(ii) and (1)(iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the Registrant pursuant to Section 13 and Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

     (2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

     (3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

     (4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

     (A) Each prospectus filed by the Registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

     (B) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of

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1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

     (5) That, for the purpose of determining liability of the Registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, the undersigned Registrant undertakes that in a primary offering of securities of the undersigned Registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned Registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

     (i) Any preliminary prospectus or prospectus of the undersigned Registrant relating to the offering required to be filed pursuant to Rule 424;

     (ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned Registrant or used or referred to by the undersigned Registrant;

     (iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned Registrant or its securities provided by or on behalf of the undersigned Registrant; and

     (iv) Any other communication that is an offer in the offering made by the undersigned Registrant to the purchaser.

     (6) That, for purposes of determining any liability under the Securities Act of 1933, each filing of the Registrant’s annual report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

     (7) That, for purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the Registrant pursuant to Rule 424(b) (1) or (4) or 497(h) under the Securities Act shall be deemed to be part of this registration statement as of the time it was declared effective.

     (8) That, for the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

     (9) To file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Securities Exchange Commission under Section 305(b)(2) of the Trust Indenture Act.

II-4

     Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Exchange Act and will be governed by the final adjudication of such issue.

II-5

SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Chatsworth, State of California, on November 10, 2010.

IRIS INTERNATIONAL, INC.
By:	/s/ César M. García
	César M. García,
	Chief Executive Officer and President

By:	/s/ Amin Khalifa
	Amin Khalifa,
	Chief Financial Officer

POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS that each individual whose signature appears below constitutes and appoints César M. García and Amin Khalifa, and each of them, his true and lawful attorneys-in-fact and agents with full power of substitution, for him and in his name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to sign any registration statement for the same offering covered by the Registration Statement that is to be effective upon filing pursuant to Rule 462(b) promulgated under the Securities Act, and all post-effective amendments thereto, and to file the same, with all exhibits thereto and all documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or his or their substitute or substitutes, may lawfully do or cause to be done or by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the dates stated.

Signature	Title	Date
/s/ César M. García César M. García	Chief Executive Officer, President and Director (Principal Executive Officer)	November 10, 2010
/s/ Amin Khalifa Amin Khalifa	Chief Financial Officer (Principal Financial and Accounting Officer)	November 10, 2010

S-1

Signature	Title	Date
/s/ Thomas H. Adams Thomas H. Adams	Director	November 10, 2010
/s/ Steven M. Besbeck Steven M. Besbeck	Director	November 10, 2010
/s/ David T. Della Penta David T. Della Penta	Director	November 10, 2010
/s/ Beth Y. Karlan Beth Y. Karlan	Director	November 10, 2010
/s/ Michael D. Matte Michael D. Matte	Director	November 10, 2010
/s/ Richard G. Nadeau Richard G. Nadeau	Director	November 10, 2010
/s/ Rick Timmins Rick Timmins	Director	November 10, 2010
/s/ Edward F. Voboril Edward F. Voboril	Director	November 10, 2010
/s/ Stephen E. Wasserman Stephen E. Wasserman	Director	November 10, 2010

S-2

EXHIBIT INDEX

Exhibit		Incorporated by Reference						Filed
Number	Description	Form	File Number	Exhibit			Filing Date	Herewith
1.1	Form of Underwriting Agreement								(1)
4.1(a)	Certificate of Incorporation, filed June 9, 1987	8-K	001-11181		3.1	(a)	September 29, 2010
4.1(b)	Certificate of Amendment of Certificate of Incorporation, filed July 9, 1993	8-K	001-11181		3.1	(b)	September 29, 2010		—
4.1(c)	Certificate of Amendment of Certificate of Incorporation, filed June 6, 2001	8-K	001-11181		3.1	(c)	September 29, 2010		—
4.1(d)	Certificate of Ownership and Merger, filed November 26, 2003	8-K	001-11181		3.1	(d)	September 29, 2010		—
4.1(e)	Certificate of Correction of Certificate of Ownership and Merger, filed December 11, 2003	8-K	001-11181		3.1	(e)	September 29, 2010		—
4.1(f)	Certificate of Designation of Rights, Preferences and Privileges of Series A Preferred Stock, filed September 27, 2010	8-K	001-11181		3.1	(f)	September 29, 2010		—
4.2	Amended and Restated Bylaws.	8-K	001-11181		3.2		July 18, 2007		—
4.3	Rights Agreement, dated as of September 24, 2010, between the Registrant and Continental Stock Transfer & Trust Company, as Rights Agent, including the Certificate of Designation of Rights, Preferences and Privileges of Series A Preferred Stock, the Form of Rights Certificate, and the Summary of Rights to Purchase Preferred Stock, attached thereto as Exhibits A, B and C, respectively.	8-K	001-11181		4.1		September 29, 2010		—
4.4	Specimen of Common Stock certificate	S-3	333-147618		4.2		November 26, 2007		—
4.5	Specimen Preferred Stock certificate of the Registrant and Form of Certificate of Designation of Preferred Stock of the Registrant								(1	)
4.6	Form of Senior Debt Indenture, between the Registrant and one or more trustees to be named								*
4.7	Form of Senior Note								(1	)
48	Form of Preferred Stock Certificate								(1	)
5.1	Opinion of Stubbs Alderton & Markiles, LLP								*
12.1	Statement of Computation of Ratios of Earning to Fixed Charges								*
23.1	Consent of Stubbs Alderton & Markiles, LLP (included in Exhibit 5.1)								*
23.2	Consent of BDO USA, LLP, independent registered public accounting firm								*
24.1	Power of Attorney (included on signature page)								*
25.1	Statement of Eligibility of Trustee under the Senior Debt Indenture								(1	)

(1) To be filed by amendment or as an exhibit to a document to be incorporated or deemed to be incorporated by reference in this registration statement, including a Current Report on Form 8-K.

Ex-1