S-8

As filed with the Securities and Exchange Commission on May 23, 2005

Registration No. 333-__________

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

TEKELEC

(Exact name of registrant as specified in its charter)

California
(State or other jurisdiction of
incorporation or organization) 95-2746131
(I.R.S. Employer
Identification No.)

26580 West Agoura Road
Calabasas, California
(Address of Principal Executive Offices) 91302
(Zip Code)

2004 Equity Incentive Plan for New Employees
2005 Employee Stock Purchase Plan
(Full titles of the plans)

RONALD W. BUCKLY, ESQ.
Senior Vice President, Corporate Affairs and General Counsel
Tekelec
26580 West Agoura Road
Calabasas, California 91302
(818) 880-5656
(Name, address and telephone number of agent for service)

Copy to:

KATHERINE F. ASHTON, ESQ.
Bryan Cave LLP
120 Broadway, Suite 300
Santa Monica, California 90401

(i)

CALCULATION OF REGISTRATION FEE

							Proposed
Title of	Amount			Proposed			Maximum
Securities	of Shares			Maximum			Aggregate			Amount of
to be	to be			Offering Price			Offering			Registration
Registered	Registered			per Share			Price			Fee
Common Stock, without par value		1,500,000	(1)(2)	$	12.285	(3)	$	18,427,500	(3)	$	2,169
Common Stock, without par value		1,000,000	(1)(4)	$	10.45	(5)	$	10,450,000	(5)	$	1,230
							TOTAL			$	3,399

(1)	This Registration Statement also covers such additional shares of Common Stock of the Registrant as may be issuable pursuant to anti-dilution provisions of the Company’s 2004 Equity Incentive Plan for New Employees (the “2004 Plan”) and the Company’s 2005 Employee Stock Purchase Plan (the “ESPP”). Pursuant to Rule 416(a) of the Securities Act of 1933, as amended (the “Securities Act”), this Registration Statement shall also cover any additional shares of the Registrant’s Common Stock that become issuable under the ESPP or the 2004 Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without the receipt of consideration that increases the number of the Registrant’s outstanding shares of Common Stock.
(2)	Represents shares issuable upon exercise of options granted and to be granted under the 2004 Plan.
(3)	Estimated pursuant to Rule 457(h) under the Securities Act solely for the purpose of calculating the amount of the registration fee on the basis of the average of the high and low reported sale prices of a share of the Registrant’s Common Stock on May 17, 2005, as reported on the Nasdaq National Market.
(4)	Represents shares issuable upon exercise of options to be granted under the ESPP.
(5)	Estimated pursuant to Rules 457(c) and 457(h) under the Securities Act of 1933, as amended, solely for the purpose of calculating the amount of the registration fee on the basis of the average of the high and low reported sale prices of a share of the Registrant’s Common Stock on May 17, 2005, as reported on the Nasdaq National Market. Under the ESPP, the purchase price of a share of Common Stock is equal to 85% of the fair market value of the Common Stock on the offering date (i.e., the first day of a 24-month offering period) or the exercise date (i.e., the last day of a six-month purchase period), whichever is less.

(ii)

TABLE OF CONTENTS

PART I: INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
PART II: INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
	Item 3. Incorporation of Documents by Reference
	Item 4. Description of Securities
	Item 5. Interests of Named Experts and Counsel
	Item 6. Indemnification of Directors and Officers
	Item 7. Exemption from Registration Claimed
	Item 8. Exhibits
	Item 9. Undertakings
SIGNATURES
INDEX TO EXHIBITS
EX-4.2
EX-5.1
EX-23.1

PART I: INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

     The documents containing the information specified in Items 1 and 2 of Part I of Form S-8 will be sent or given to the holders of options as specified in Rule 428(b)(1) under the Securities Act. In accordance with the instructions to Part I, those documents are not filed with the Commission as part of this registration statement or a prospectus under Rule 424 of the Securities Act.

PART II: INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

          The following documents and information previously filed with the Securities and Exchange Commission are hereby incorporated by reference:

          Item 3(a)

The Registrant’s Annual Report on Form 10-K for the fiscal year ended December 31, 2004.

          Item 3(b)

The Registrant’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2005.

The Registrant’s Current Reports on Form 8-K filed with the Commission on March 24 2005, April 7, 2005, April 13, 2005 and May 6, 2005.

          Item 3(c)

Item 1 of the Registrant’s Registration Statement on Form 8-A (Registration No. 0-15135) filed with the Commission on November 12, 1986, pursuant to Section 12 of the Securities Exchange Act of 1934.

          All documents subsequently filed by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, prior to the filing of a post-effective amendment which indicates that all securities offered have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be part hereof from the date of filing such documents.

Item 4. Description of Securities.

          Not Applicable.

Item 5. Interests of Named Experts and Counsel.

          Not Applicable.

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Item 6. Indemnification of Directors and Officers.

          Section 317 of the California General Corporation Law provides that a corporation may indemnify corporate “agents” (including directors, officers and employees of the corporation) against expenses, judgments, fines, settlements and other amounts actually and reasonably incurred in connection with defending non-derivative actions if such person acted in good faith and in a manner such person reasonably believed to be in the best interests of the corporation and, in the case of a criminal proceeding, had no reasonable cause to believe the conduct of such person was unlawful, and against expenses actually and reasonably incurred in connection with defending derivative actions if such person acted in good faith and in a manner such person believed to be in the best interests of the corporation and its shareholders. Indemnification is obligatory to the extent that an agent of a corporation has been successful on the merits in defense of any such proceeding against such agent, but otherwise may be made only upon a determination in each instance either by a majority vote of a quorum of the Board of Directors (other than directors involved in such proceeding), by independent legal counsel if such a quorum of directors is not obtainable, by the shareholders (other than shareholders to be indemnified), or by the court, that indemnification is proper because the agent has met the applicable statutory standards of conduct. Corporations may also advance expenses incurred in defending proceedings against corporate agents, upon receipt of an undertaking that the agent will reimburse the corporation unless it is ultimately determined that the agent is entitled to be indemnified against expenses reasonably incurred.

          The indemnification provided by Section 317 of the California General Corporation Law is not deemed to be exclusive of any other rights to which agents of the Registrant seeking indemnification may be entitled under any bylaw, agreement, vote of shareholders or disinterested directors, or otherwise, both as to action in an official capacity and as to action in another capacity while holding such office, to the extent such additional rights are authorized in the articles of the corporation. Article V of the Registrant’s Amended and Restated Articles of Incorporation authorizes the Registrant to provide for indemnification of its agents for breach of duty to the Registrant and its shareholders, through bylaw provisions or through agreements with such agents, or both, in excess of the indemnification otherwise permitted by Section 317, subject to the limits on such excess indemnification set forth in Section 204 of the California General Corporation Law.

          Article VI of the Registrant’s Amended and Restated Bylaws provides for the mandatory indemnification of all directors and executive officers of the Company to the maximum extent and in the manner permitted by Section 317. Additionally, the Registrant has entered into Indemnification Agreements with its directors and executive officers under which the Registrant has undertaken to indemnify each such director or executive officer to the fullest extent permitted by it’s Amended and Restated Articles of Incorporation, Amended and Restated Bylaws and applicable law against all expenses, liability and loss (which are not paid by insurance or otherwise by the Registrant) reasonably incurred or suffered by such agent in connection with the defense of any action or proceeding to which the agent was or is a party or is threatened to be made a party by reason of conduct in his capacity as an officer or director, or in which the agent is or may be involved by reason of the fact that he is or was serving as an officer or director of the Registrant. These indemnification agreements do not require the Registrant to:

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•   indemnify any director or executive officer where such indemnification for any acts or omissions or transactions would be in violation of the California General Corporation Law or other applicable law, including without limitation imdemnification for breach of duty to the corporation or its shareholders under circumstances in which such indemnity would be expressly prohibited by Section 317 of the California General Corporation Law;

•   indemnify or advance expenses to any director or executive officer with respect to claims voluntarily initiated by such director or executive officer and not by way of defense, other than with repect to claims brought in order to enforce the indemnification agreement itself or a right under Section 317 of the California General Corporation Law, or other applicable law, unless such claim has been approved by the Registrant;

•   indemnify any director or executive officer for any expenses incurred with respect to claims brought to enforce the indemnification agreement itself or a right under Section 317 of the California General Corporation Law, or other applicable law, which claim was determined by a court of competent jurisdiction to be frivolous or not in good faith;

•   indemnify any director or executive officer for any expenses for which such director or executive officer has otherwise received payment pursuant to a liability insurance policy, the Registrant’s Amended and Restated Articles of Incorporation or Amended and Restated Bylaws, any applicable provisions of the California General Corporation Law, or any other agreement; or

•   indemnify any director or executive officer for expenses or profits arising from the purchase and sale by such director or executive officer of securities in violation of Section 16(b) of the Securities Exchange Act of 1934.

          The Registrant also maintains on behalf of its directors and officers insurance protection against certain liabilities arising out of the discharge of their duties.

Item 7. Exemption from Registration Claimed.

          Not applicable.

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Item 8. Exhibits.

Exhibit
Number
4.1	Tekelec 2004 Equity Incentive Plan for New Employees(1) and Amendment No. 1(2), Amendment No. 2(2) and Amendment No. 3(3) thereto
4.2	Tekelec 2005 Employee Stock Purchase Plan
5.1	Opinion of Bryan Cave LLP
23.1	Consent of PricewaterhouseCoopers LLP
23.2	Consent of Bryan Cave LLP (included in Exhibit 5.1)
24.1	Power of Attorney (see page 6 of this Registration Statement)

(1)	Incorporated by reference to the Registrant’s Quarterly Report on Form 10-Q (File No. 0-15135) for the quarter ended September 30, 2004, as filed with the Commission on November 9, 2004.
(2)	Incorporated by reference to the Registrant’s Current Report on Form 8-K (File No. 0-15135) as filed with the Commission on March 24, 2005.
(3)	Incorporated by reference to the Registrant’s Current Report on Form 8-K (File No. 0-15135) as filed with the Commission on May 6, 2005.
(4)	Incorporated by reference to the Registrant’s Quarterly Report on Form 10-Q (File No. 0-15135) for the quarter ended March 31, 2005, as filed with the Commission on May 9, 2005.

Item 9. Undertakings.

     (a) 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;

               (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;

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          Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed by the Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in 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.

     (b) 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 Section 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.

     (c) 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 Act of 1933 and will be governed by the final adjudication of such issue.

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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-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Calabasas, State of California, on May 20, 2005.

TEKELEC
By:	/s/ Frederick M. Lax
	Frederick M. Lax,
	Chief Executive Officer and President

POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Frederick M. Lax and Ronald W. Buckly, or either of them, his attorneys-in-fact and agents, each with full power of substitution for him and in his name, place and stead, in any and all capacities, to sign any or all amendments (including, without limitation, post-effective amendments and documents in connection therewith) to this Registration Statement, and to file the same with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto each of said attorneys-in-fact and agents full power and authority to do so and perform each and every act and thing requisite and necessary to be done in connection with this Registration Statement, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that either of said attorneys-in-fact and agents, or his substitute or substitutes, may lawfully do or cause to be done 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 indicated.

Signature	Title	Date
	Director, Chief Executive Officer and	May 20, 2005
/s/ Frederick M. Lax	President (Principal Executive Officer)
Frederick M. Lax
/s/ William H. Everett	Senior Vice President and Chief Financial	May 20, 2005
William H. Everett	Officer (Principal Financial and Accounting Officer)
/s/ Jean-Claude Asscher	Chairman of the Board	May 20, 2005
Jean-Claude Asscher
/s/ Robert V. Adams	Director	May 20, 2005
Robert V. Adams
/s/ Daniel L. Brenner	Director	May 20, 2005
Daniel L. Brenner

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Signature	Title	Date
/s/ Mark A. Floyd	Director	May 20, 2005
Mark A. Floyd
	Director
Martin A. Kaplan
/s/ Jon F. Rager	Director	May 20, 2005
Jon F. Rager

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INDEX TO EXHIBITS

Exhibit
Number	Exhibit
4.2	Tekelec 2005 Employee Stock Purchase Plan
5.1	Opinion of Bryan Cave LLP
23.1	Consent of PricewaterhouseCoopers LLP

EX-4.2

EXHIBIT 4.2

TEKELEC

2005 EMPLOYEE STOCK PURCHASE PLAN

     The following constitutes the provisions of the Tekelec 2005 Employee Stock Purchase Plan (the “Plan”).

     1. Purpose. The purpose of the Plan is to provide employees of Tekelec (the “Company”) and its subsidiaries with an opportunity to purchase Common Stock of the Company through payroll deductions. It is the intention of the Company that the Plan qualify as an “Employee Stock Purchase Plan” under Section 423 of the Internal Revenue Code of 1986, as amended (the “Code”). The provisions of the Plan shall, accordingly, be construed so as to extend and limit participation in a manner consistent with the requirements of that section of the Code, as amended from time to time.

     2. Certain Definitions.

          (a) “Board” shall mean the Board of Directors of the Company or any committee thereof designated by the Board of Directors of the Company in accordance with Section 13 of the Plan.

          (b) “Code” shall mean the Internal Revenue Code of 1986, as amended, and any applicable regulations promulgated thereunder.

          (c) “Common Stock” shall mean the common stock of the Company.

          (d) “Compensation,” unless otherwise determined by the Board of Directors of the Company, means total cash compensation from employment reportable on Form W-2 including, without limitation, regular straight-time gross earnings, overtime pay, shift premium, incentive compensation, bonuses, commissions, but expressly excluding expense reimbursements, automobile allowances, relocation benefits, equity-based compensation, gains realized in connection with the exercise of stock options or participation in a stock option or purchase programs and contributions by the Company to qualified deferred compensation plans.

          (e) “Eligible Subsidiary” means any subsidiary that from time to time is expressly designated by the Board of Directors as being an “Eligible Subsidiary” for purposes of the Plan.

          (f) “Employee” means any person, including an officer, who is customarily employed for more than 20 hours per week by the Company or its Eligible Subsidiary and more than five months in any calendar year. For purposes of the Plan, the employment relationship shall be treated as continuing intact while the individual is on sick leave or other leave of absence approved by the Company. Where the period of leave exceeds 90 days and the individual’s right to reemployment is not guaranteed either by statute or by contract, the employment relationship shall be deemed to have terminated on the 91st day of such leave.

          (g) “Enrollment Date” means the first Trading Day of each Offering Period.

          (h) “Exercise Date” means the last Trading Day of each Purchase Period.

          (i) “Fair Market Value” means, as of any date, the fair market value of one share of Common Stock, determined as follows:

          (i) If the Common Stock is listed on a national or regional securities exchange or market system, including without limitation the Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its fair market value shall be the closing sales price for such stock (or the mean of the closing bid and asked prices, if no sales were reported) as reported on such date (or, if such day is not a Trading Day, on the most recent Trading Day prior to such date) in The Wall Street Journal or such other source as the Board deems reliable;

          (ii) If the Common Stock is regularly quoted by a recognized securities dealer but sales prices are not reported, its fair market value shall be the mean of the closing bid and asked prices for the Common Stock on such date (or, if such day is not a Trading Day, on the most recent Trading Day prior to such date), as reported in The Wall Street Journal or such other source as the Board deems reliable; or

          (iii) In the absence of an established market for the Common Stock, the fair market value thereof shall be determined in good faith by the Board.

          (j) “Offering Periods” shall mean the periods of approximately 24 months during which an option granted pursuant to the Plan may be exercised, commencing on the first Trading Day on or after August 1 and February 1 of each year and terminating on the last Trading Day in the period prior to the 24-month anniversary of such date. The first Offering Period under the Plan shall commence on August 1, 2005 and shall end on July 31, 2007, unless earlier terminated in accordance with the terms of this Plan. The duration and timing of Offering Periods may be changed pursuant to Section 4 of this Plan.

          (k) “Purchase Period” shall mean the approximately six-month periods commencing on the first Trading Day on or after August 1 and February 1 of each year during the term of this Plan and ending with the last Trading Day prior to the commencement of the next Purchase Period. The first Purchase Period of any Offering Period shall commence on the Enrollment Date and end on the last Trading Day prior to the first day of the next Purchase Period. The first Purchase Period under the Plan shall commence on August 1, 2005 and end on January 31, 2006.

          (l) “Purchase Price” shall mean 85% of the Fair Market Value of a share of Common Stock on the Enrollment Date or on the Exercise Date, whichever is lower; provided, however, that the Purchase Price may be adjusted by the Board pursuant to Section 19.

          (m) “Subsidiary” means any corporation described in Section 424 of the Code in which the Company owns, directly or indirectly, 50% or more of the voting shares.

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          (n) “Trading Day” shall mean a day on which national stock exchanges and The Nasdaq Stock Market are open for trading.

     3. Eligibility.

          (a) General Rule. Any Employee, as defined in Section 2, who shall have completed at least 30 days of continuous employment by the Company or its Eligible Subsidiaries on the date his or her participation in the Plan is effective shall be eligible to participate in the Plan, subject to the limitations imposed by Section 423(b) of the Code.

          (b) Exceptions. Any provisions of the Plan to the contrary notwithstanding, no Employee shall be granted an option under the Plan if:

          (i) immediately after the grant, such Employee (or any other person whose stock ownership would be attributed to such Employee pursuant to Section 424(d) of the Code) would own shares and/or hold outstanding options to purchase shares possessing five percent or more of the total combined voting power or value of all classes of shares of the Company or of any Subsidiary; or

          (ii) such option would permit the Employee’s rights to purchase shares under all employee stock purchase plans of the Company and its Subsidiaries to accrue (i.e., become exercisable) at a rate which exceeds $25,000 of fair market value of such shares (determined at the time such option is granted) for any calendar year in which such option is outstanding at any time.

     4. Offering Periods. The Plan shall be implemented by consecutive, overlapping Offering Periods with a new Offering Period commencing on the first Trading Day on or after August 1 and February 1 of each year, or on such other date as the Board shall determine, and continuing thereafter until terminated in accordance with Section 20 hereof. The first Offering Period under the Plan shall commence on August 1, 2005. The Board shall have the power to change the duration of Offering Periods (including the commencement dates thereof) with respect to future offerings without shareholder approval if such change is announced at least five days prior to the scheduled beginning of the first Offering Period to be affected thereafter. Participation in one offering under the Plan shall neither limit nor require participation in any other offering.

     5. Participation. An eligible Employee may become a participant in the Plan by completing and signing a subscription agreement authorizing payroll deductions on a form provided by the Company (the “Subscription Agreement”) and by filing it with the Company’s payroll office not less than three business days prior to the start of the applicable Offering Period with respect to which it is to be effective unless a later time for filing the Subscription Agreement has been set by the Company with respect to a given offering. An Employee’s authorization and participation in the Plan shall become effective on the first Enrollment Date following the timely filing of his or her Subscription Agreement and shall remain effective until revoked by the participant by the filing of a Payroll Deduction Authorization Change or Withdrawal form as described in Section 10(a) hereof or until changed by the filing of a Payroll Deduction Authorization Change or Withdrawal form providing for a change in the participant’s payroll deduction rate. An Employee who becomes

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eligible to participate in the Plan after the commencement of an Offering Period or who is eligible but declines to participate prior to the commencement of such Offering Period may not become a participant in the Plan until the commencement of the next Offering Period.

     6. Payroll Deductions.

          (a) Payroll deductions for a participant shall commence on the first payroll following the Enrollment Date and shall end on the last payroll in the Offering Period as to which such authorization is applicable, unless sooner terminated by the participant as provided in Section 10 hereof.

          (b) At the time a participant files his or her Subscription Agreement with the Company, he or she shall elect to have payroll deductions made on each payday during the next Offering Period at a percentage rate equal to a positive whole number not exceeding 15%, or such other maximum rate as may be determined from time to time by the Board subject to the provisions of Section 19 hereof, of the Compensation which would otherwise be payable to such participant on each such payday.

          (c) Payroll deductions for a participant shall commence on the first payday following the date on which a participant’s payroll deduction authorization becomes effective and shall automatically continue from Offering Period to Offering Period (and from Purchase Period to Purchase Period within an Offering Period) until changed or terminated by the participant in accordance with the terms hereof.

          (d) All payroll deductions authorized by a participant shall be credited to the participant’s individual account under the Plan. A participant may not make any additional payments into such account.

          (e) A participant may terminate his or her participation in the Plan at any time prior to the termination of the Offering Period as provided in Section 10 hereof, or may increase or decrease the rate of his or her payroll deductions for a future Offering Period or Purchase Period by completing and filing with the Company at least three business days prior to the start of the next Purchase Period or Offering Period, as applicable, a new Subscription Agreement authorizing a change in payroll deduction rate. The Board may, in its discretion, limit the number of participation rate changes during any Offering Period. The change in rate shall be effective as of the first full payday of the next Purchase Period or Offering Period, as applicable. A participant’s Subscription Agreement shall remain in effect for successive Offering Periods (and Purchase Periods within an Offering Period) unless terminated as provided in Section 10 hereof.

     7. Grant of Option. On the Enrollment Date of each Offering Period, each participant in such Offering Period shall automatically be granted an option to purchase on each Exercise Date during such Offering Period (at the applicable Purchase Price) up to a number of shares of the Company’s Common Stock determined by dividing such Employee’s payroll deductions accumulated prior to such Exercise Date and retained in the participant’s account as of the Exercise Date by the applicable Purchase Price; provided, however, that in no event shall an Employee be permitted to purchase during each Purchase Period more than a number of shares determined by

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dividing $12,500 by the Fair Market Value of a share of the Company’s Common Stock (subject to any adjustment pursuant to Section 19) on the Enrollment Date; and provided further that such grant of options and purchase shall be subject to the limitations set forth in Sections 3(b) and 12 hereof. The Board may, for future Offering Periods, increase or decrease, in its absolute discretion, the maximum number of shares of the Company’s Common Stock an Employee may purchase during each Purchase Period of an Offering Period. Exercise of the option shall occur as provided in Section 8 hereof, unless the participant has withdrawn pursuant to Section 10 hereof. The option shall expire on the last day of the Offering Period.

     8. Exercise of Option.

          (a) Unless a participant withdraws from the Plan as provided in Section 10, his or her option for the purchase of shares shall be exercised automatically on each Exercise Date of the Offering Period, and the accumulated payroll deductions credited to a participant’s account on the Exercise Date will be applied to purchase whole shares of the Company’s Common Stock (up to the maximum number subject to option as determined in Section 7 hereof) at the Purchase Price. Any amount credited to a participant’s account and not applied to the purchase of Common Stock by reason of the limitation on the number of shares subject to option shall be refunded promptly to such participant after the Exercise Date, provided that any amount remaining in a participant’s account and representing a fractional share shall be carried over and applied to the purchase of shares in the subsequent Purchase Period or Offering Period if the participant participates in the subsequent offering. During his or her lifetime, a participant’s option to purchase shares hereunder is exercisable only by the participant.

          (b) If the Board determines that, on a given Enrollment Date or Exercise Date, the number of shares with respect to which options are to be granted or exercised, as applicable, may exceed (i) the number of shares of Common Stock that were available for sale under the Plan on the Enrollment Date of the applicable Offering Period, or (ii) the number of shares available for sale under the Plan on such Exercise Date, the Board may in its sole discretion (x) provide that the Company shall make a pro rata allocation of the shares of Common Stock available for grant or purchase on such Enrollment Date or Exercise Date, as applicable, in as uniform a manner as shall be practicable and as it shall determine in its sole discretion to be equitable among all participants granted options to purchase Common Stock on such Enrollment Date or exercising options to purchase Common Stock on such Exercise Date, as applicable, and continue all Offering Periods then in effect, or (y) provide that the Company shall make a pro rata allocation of the shares available for grant or purchase on such Enrollment Date or Exercise Date, as applicable, in as uniform a manner as shall be practicable and as it shall determine in its sole discretion to be equitable among all participants granted options to purchase Common Stock on such Enrollment Date or exercising options to purchase Common Stock on such Exercise Date, and terminate any or all Offering Periods then in effect pursuant to Section 19 hereof. The Company may make a pro rata allocation of the shares available on the Enrollment Date of any applicable Offering Period pursuant to the preceding sentence, notwithstanding any authorization of additional shares for issuance under the Plan by the Company’s shareholders subsequent to such Enrollment Date. In the event of any pro rata allocation of shares, the Company shall give written notice of such

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allocation to each participant affected thereby and shall reduce the rate of payroll deductions, if necessary.

     9. Delivery; Holding Period. As promptly as practicable after each Exercise Date on which a purchase of shares occurs, the Company shall arrange for the issuance and delivery to, or credit to the account of, each participant, as appropriate, of the shares purchased upon exercise of his or her option. At the election of the Company, the issuance and delivery of the shares purchased upon exercise of a participant’s option may be effected by transfer (electronic or otherwise in the discretion of the Company) of such shares to a securities account maintained in the participant’s name. The shares purchased upon exercise of any option granted to a participant may not be assigned, transferred, pledged or otherwise disposed of in any way (other than by will or by the laws of descent and distribution) for a period of 90 days following the exercise of the option; provided, however, that the Board of Directors may, in its sole discretion, permit an assignment, transfer, pledge or other disposition of such shares at such other time as the Company’s Board of Directors may determine in the event that the participant has suffered a hardship, as determined by the Company’s Board of Directors in its sole discretion. Shares purchased upon exercise of any option granted to a participant and subject to the above restrictions may include a legend indicating that such shares may not be transferred, pledged or otherwise disposed of for 90 days from the date of issue.

     10. Withdrawal; Termination of Employment.

          (a) A participant may terminate his or her participation in an offering under the Plan and withdraw all, but not less than all, of the payroll deductions credited to his or her account under the Plan at any time prior to an Exercise Date by giving written notice of withdrawal to the Company on a Payroll Deduction Authorization Change or Withdrawal form provided for such purpose. In such case, all of the participant’s payroll deductions credited to his or her account shall be paid to him or her promptly after receipt of his or her notice of withdrawal, his or her option for the Offering Period shall be automatically canceled, and no further payroll deductions for the purchase of shares shall be made for such Offering Period. If a participant withdraws from an Offering Period, payroll deductions shall not resume at the beginning of the succeeding Offering Period unless the participant delivers to the Company a new Subscription Agreement in accordance with Section 5 hereof.

          (b) A participant may terminate his or her participation in the Plan effective as of the first day of the next Purchase Period or Offering Period by giving written notice of withdrawal to the Company on a Payroll Deduction Authorization Change or Withdrawal form provided for such purpose. In such case, the participant’s payroll deductions will continue through the end of the Purchase Period or Offering Period in which the notice of withdrawal is given, all amounts deducted from the participant’s Compensation during such Purchase Period or Offering Period will be applied to the purchase of Common Stock pursuant to the Plan, and following such termination of participation no further payroll deductions for the purchase of shares shall be made except pursuant to a new Subscription Agreement delivered in accordance with Section 5 hereof.

6

          (c) Upon termination of a participant’s employment for any reason, including retirement or death, as soon as practicable after such termination, the payroll deductions credited to his or her account shall be returned to him or her or, in the case of his or her death, to the person or persons entitled thereto under Section 14, and his or her option shall be automatically canceled.

          (d) In the event an Employee fails to remain in the continuous employ of the Company or its Eligible Subsidiaries for more than 20 hours per week during the Offering Period in which the Employee is a participant, he or she will be deemed to have elected to withdraw from the Plan and the payroll deductions credited to his or her account will be returned to him or her and his or her option will be canceled.

          (e) A participant’s withdrawal from an offering shall not have any effect upon his or her eligibility to participate in a subsequent offering or in any similar plan which may hereafter be adopted by the Company.

     11. Interest. No interest shall accrue on the payroll deductions of a participant in the Plan.

     12. Stock.

          (a) The maximum number of shares of the Company’s Common Stock which shall be made available for sale under the Plan shall be 1,000,000 shares, subject to adjustment upon changes in capitalization of the Company as provided in Section 18(a) hereof, together with a cumulative annual increase to the number of shares reserved for issuance thereunder on August 1, 2006 and on each August 1 thereafter equal to the lesser of (i) 500,000 shares, (ii) 1% of the number of outstanding shares of Common Stock of the Company on the date of such increase or (iii) such amount as may be determined by the Board. The shares to be sold to participants in the Plan will be authorized but unissued shares. Upon the cancellation of any option granted under the Plan, the shares subject thereto shall return to the Plan and become available for options thereafter granted under the Plan.

          (b) A participant will have no interest or voting right in shares covered by his or her option until such option has been exercised.

          (c) Shares to be delivered to a participant under the Plan shall, as specified in the participant’s Subscription Agreement, be registered in the name of the participant or in the name of the participant and his or her spouse.

     13. Administration. The Plan shall be administered by the Board or a committee of members of the Board appointed by the Board. The Board or its committee shall have full and exclusive discretionary authority to construe, interpret and apply the terms of the Plan, to determine eligibility and to adjudicate all disputed claims filed under the Plan. Every finding, decision and determination made by the Board or its committee shall, to the fullest extent permitted by law, be final and binding upon all parties.

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     14. Designation of Beneficiary.

          (a) A participant may file a written designation of a beneficiary who is to receive any shares and cash, if any, from the participant’s account under the Plan in the event of such participant’s death subsequent to the Exercise Date on which an option is exercised but prior to delivery to him or her of such shares and cash. In addition, a participant may file a written designation of a beneficiary who is to receive any cash from the participant’s account under the Plan in the event of such participant’s death prior to exercise of the option. If a participant is married and the designated beneficiary is not the spouse, spousal consent shall be required for such designation to be effective.

          (b) Such designation of beneficiary may be changed by the participant at any time by written notice. In the event of the death of a participant and in the absence of a valid designation of a beneficiary who is living at the time of such participant’s death, the Company shall deliver such shares and/or cash to the executor or administrator of the estate of the participant; or if no such executor or administrator has been appointed (to the knowledge of the Company), the Company, in its discretion, may deliver such shares and/or cash to the spouse or to any one or more dependents or relatives of the participant; or if no spouse, dependent or relative is known to the Company, then to such other person as the Company may designate.

     15. Transferability. Neither payroll deductions credited to a participant’s account nor any rights with regard to the exercise of an option or to receive shares under the Plan may be assigned, transferred, pledged or otherwise disposed of in any way (other than by will, the laws of descent and distribution, pursuant to a qualified domestic relations order as defined by the Code or Title I of the Employee Retirement Income Security Act, or the rules thereunder, or as provided in Section 14 hereof) by the participant. Any such attempt at assignment, transfer, pledge or other disposition shall be without effect, except that the Company may treat such act as an election to withdraw funds from an Offering Period in accordance with Section 10 hereof.

     16. Use of Funds. All payroll deductions received or held by the Company on behalf of a participant under the Plan may be used by the Company for any corporate purpose, and the Company shall not be obligated to segregate such payroll deductions.

     17. Reports. Individual accounts will be maintained for each participant in the Plan. Individual statements of account will be given to participating Employees at least annually, which statements shall set forth the amounts of payroll deductions, the Purchase Price, the number of shares purchased and the remaining cash balance, if any, in a participant’s account.

     18. Adjustments upon Changes in Capitalization or Control.

          (a) Changes in Capitalization. Subject to any required action by the shareholders of the Company, the number of shares of Common Stock covered by each option under the Plan which has not yet been exercised and the number of shares of Common Stock which has been authorized for issuance under the Plan but has not yet been placed under option or which has been returned to the Plan upon the cancellation of an option, as well as the option price per share of Common Stock covered by each option under the Plan which has not yet been exercised, shall be

8

proportionately adjusted for any increase or decrease in the number of issued shares of Common Stock resulting from a stock split, reverse stock split, stock dividend, combination of the Common Stock, or any other increase or decrease in the number of shares of Common Stock effected without receipt of consideration by the Company; provided, however, that conversion of any convertible securities of the Company shall not be deemed to have been “effected without receipt of consideration.” Such adjustment shall be made by the Board, whose determination in that respect shall be final, binding and conclusive. Except as expressly provided herein, no issue by the Company of shares of stock of any class, or securities convertible into shares of stock of any class, shall affect, and no adjustment by reason thereof shall be made with respect to, the number or price of shares of Common Stock subject to option.

          (b) Dissolution or Liquidation. In the event of the proposed dissolution or liquidation of the Company, the Offering Period then in progress shall be shortened by setting a new Exercise Date (the “New Exercise Date”), and shall terminate immediately prior to the consummation of such proposed dissolution or liquidation, unless provided otherwise by the Board. The New Exercise Date shall be before the date of the Company’s proposed dissolution or liquidation. The Board shall notify each participant in writing, at least ten business days prior to the New Exercise Date, that the Exercise Date for the participant’s option has been changed to the New Exercise Date and that the participant’s option shall be exercised automatically on the New Exercise Date, unless prior to such date the participant has withdrawn from the Offering Period as provided in Section 10 hereof.

          (c) Merger or Asset Sale. In the event of a proposed sale of all or substantially all of the assets of the Company, or the merger of the Company with or into another corporation, each outstanding option shall be assumed or an equivalent option substituted by the successor corporation or a parent or subsidiary of the successor corporation. In the event that the successor corporation refuses to assume or substitute for the option, any Purchase Periods then in progress shall be shortened by setting a new Exercise Date (the “Modified Exercise Date”) and any Offering Periods then in progress shall end on the Modified Exercise Date. The Modified Exercise Date shall be before the date of the Company’s proposed sale or merger. The Board shall notify each participant in writing, at least ten business days prior to the Modified Exercise Date, that the Exercise Date for the participant’s option has been changed to the Modified Exercise Date and that the participant’s option shall be exercised automatically on the Modified Exercise Date, unless prior to such date the participant has withdrawn from the Offering Period as provided in Section 10 hereof.

          (d) No fractional shares of Common Stock shall be issuable on account of any adjustment described herein, and the aggregate number of shares into which shares then covered by an option, when changed as the result of such adjustment, shall be reduced to the largest number of whole shares resulting from such adjustment, unless the Board, in its sole discretion, shall determine to issue scrip certificates in respect to any fractional shares, which scrip certificates, in such event, shall be in a form and have such terms and conditions as the Board in its discretion shall prescribe.

     19. Amendment or Termination. The Board of Directors of the Company may at any time and for any reason terminate or amend the Plan. Except as provided in Section 18 hereof, no

9

such termination can affect options previously granted, provided that an Offering Period may be terminated by the Board of Directors on any Exercise Date if the Board determines that the termination of the Offering Period or the Plan is in the best interests of the Company and its shareholders. Except as provided in Section 18 and this Section 19, no amendment may make any change in any option theretofore granted which adversely affects the rights of any participant without the prior written consent of such participant:

          (a) To the extent necessary to comply with Section 423 of the Code (or any successor rule or provision or any other applicable law, regulation or stock exchange rule), the Company shall obtain shareholder approval of any amendment to the Plan in such a manner and to such a degree as is required.

          (b) Without shareholder approval and without regard to whether any participant rights may be considered to have been “adversely affected,” the Board (or its committee) shall be entitled to change the Offering Periods, limit the frequency and/or number of changes in the amount withheld during an Offering Period, establish the exchange ratio applicable to amounts withheld in a currency other than U.S. dollars, permit payroll withholding in excess of the amount designated by a participant in order to adjust for delays or mistakes in the Company’s processing of properly completed withholding elections, establish reasonable waiting and adjustment periods and/or accounting and crediting procedures to ensure that amounts applied toward the purchase of Common Stock for each participant properly correspond with amounts withheld from the participant’s Compensation, and establish such other limitations or procedures as the Board (or its committee) determines in its sole discretion advisable which are consistent with the Plan.

          (c) In the event the Board determines that the ongoing operation of the Plan may result in unfavorable financial accounting consequences, the Board may, in its discretion and to the extent necessary or desirable, modify or amend the Plan to reduce or eliminate such accounting consequence including, but not limited to:

          (i) altering the Purchase Price for any Offering Period including an Offering Period underway at the time of the change in Purchase Price;

          (ii) shortening any Offering Period so that Offering Period ends on a new Exercise Date, including an Offering Period underway at the time of the Board action; and

          (iii) allocating shares.

          Such modifications or amendments shall not require shareholder approval or the consent of any Plan participants.

     20. Term of Plan. The Plan shall become effective upon its approval by vote of the outstanding shares of the Company as provided in Section 22. The Plan shall continue in effect for a term of ten years following the date of approval of the Plan by the Board of Directors unless sooner terminated under Sections 19 or 22 hereof.

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     21. Notices. All notices or other communications (i) by a participant to the Company in connection with the Plan shall be deemed to have been duly given when received in the form specified by the Company at the location, or by the person, designated by the Company for the receipt thereof and (ii) by the Company to a participant in connection with the Plan shall be deemed to have been duly given when received by the participant or, if earlier, five days after deposit in the United States mail by certified or registered mail, return receipt requested, first class postage prepaid, addressed to the participant at his or her address as shown on the records of the Company or as such participant may request by written notice to the Company hereunder.

     22. Shareholder Approval. Notwithstanding anything to the contrary herein, the effectiveness of the Plan shall be expressly subject to approval by the Company’s shareholders prior to August 31, 2005 by the affirmative vote of the holders of a majority of the outstanding shares of stock of the Company present or represented and entitled to vote thereon at a shareholder meeting duly held or by written consent in accordance with applicable law.

     23. Automatic Transfer to Low Price Offering Period. To the extent permitted by any applicable laws, regulations or stock exchange or market system rules, if the Fair Market Value of the Common Stock on any Exercise Date in an Offering Period is lower than the Fair Market Value of the Common Stock on the Enrollment Date of such Offering Period, then all participants in such Offering Period shall be automatically withdrawn from such Offering Period immediately after the exercise of their option on such Exercise Date and automatically re-enrolled in the immediately following Offering Period as of the first day thereof in accordance with the terms and conditions of their Subscription Agreement then in effect.

     24. No Enlargement of Employee Rights. The Plan is purely voluntary on the part of the Company, and the continuance of the Plan shall not be deemed to constitute a contract between the Company and any Employee, or to be consideration for or a condition of the employment of any Employee. Nothing contained in this Plan shall be deemed to give any Employee the right to be retained in the employ of the Company, its parent, any Subsidiary or a successor corporation, or to interfere with the right of the Company or any such corporations to discharge or retire any Employee thereof at any time. No Employee shall have any right to or interest in options authorized hereunder prior to the grant of an option to such Employee, and upon such grant he or she shall have only such rights and interests as are expressly provided herein, subject, however, to all applicable provisions of the Company’s Articles of Incorporation, as the same may be amended from time to time.

     25. Information to Participants. The Company shall provide without charge to each participant in the Plan copies of such annual and periodic reports as are provided by the Company to its shareholders generally.

     26. Governing Law. To the extent that federal laws do not otherwise control, the Plan and all determinations made or actions taken pursuant hereto shall be governed by the laws of the State of California, without regard to the conflicts of laws rules thereof.

     27. Tax Withholding. If at any time the Company or any Eligible Subsidiary is required, under applicable laws and regulations, to withhold, or to make any deduction of, any taxes or take

11

any other action in connection with any exercise of an option granted hereunder or any disposition of shares of Common Stock issued hereunder, the participant must make adequate provision for the Company’s federal, state or other tax withholding obligations which arise from such exercise or disposition. The Company or such Eligible Subsidiary shall have the right to deduct or withhold from the participant’s compensation the amount necessary for the Company or such Eligible Subsidiary to meet applicable withholding obligations.

     28. Securities Law Compliance. No shares of Common Stock may be issued upon the exercise of any option under the Plan until all requirements of applicable federal, state, foreign or other securities laws with respect to the purchase, sale and issuance of shares of Common Stock shall have been satisfied. If any action must be taken because of such requirements, then the purchase, sale and issuance of shares shall be postponed until such action can reasonably be taken. Upon request by the Company, an Employee shall deliver to the Company such information, representations or undertakings as the Company may reasonably request in order to comply with any registration requirements or exemptions therefrom of applicable securities laws. The Company may require any securities so issued to bear a legend, may give its transfer agent instructions, and may take such other steps as in its judgment are reasonably required to prevent any violation of applicable securities laws.

*     *    *

12

TEKELEC

2005 EMPLOYEE STOCK PURCHASE PLAN

FORM OF
SUBSCRIPTION AGREEMENT

Instructions: Please print or type all information except your signature.

Name:
	First	Middle	Last
Address:

Social Security No.:                                  —                                  —                                 

Employee No.: Employment Start Date:

ORIGINAL APPLICATION

1.   I hereby elect to participate in the Tekelec 2005 Employee Stock Purchase Plan (the “Plan”) in accordance with this Subscription Agreement and subject to the terms and conditions of the Plan.

2.   I hereby authorize Tekelec to make regular payroll deductions, at the rate indicated below and in accordance with the terms of the Plan, from the total Compensation (as defined in the Plan) including overtime, bonuses, commissions and other earnings, if any, paid to me during each offering period during which I remain a participant in the Plan:

(circle one)	1	%	2	%	3	%	4	%	5	%	6	%		7	%	8	%	9	%
	10	%	11	%	12	%	13	%	14	%	15	%	of compensation

3.   I understand that payroll deductions at the indicated rate will continue from offering period to offering period unless I become ineligible to participate in the Plan or I file the Payroll Deduction Authorization Change or Withdrawal portion of this form below.

4.   I understand that the deducted amounts will be applied automatically to the purchase of shares of Tekelec Common Stock at the end of each offering period unless I elect to cancel my option and withdraw from the Plan by filing the Payroll Deduction Authorization Change or Withdrawal portion of this form below.

5.   I hereby acknowledge that I have received and read a copy of Tekelec’s most recent Prospectus describing the terms and provisions of the Plan and understand the information therein and the risks of participating in the Plan.

6.	Shares purchased for me under the Plan should be issued in the name(s) of:
7.	I hereby agree to be bound by the terms of the Plan. The effectiveness of this Subscription Agreement is dependent upon my eligibility to participate in the Plan.
8.	I will promptly (a) notify Tekelec if I have sold, transferred, gifted or otherwise disposed of any shares purchased for me under the Plan at any time within two years after the end of the offering period in which such shares were purchased and (b) provide Tekelec with all requested information regarding such transaction.
9.	In the event of my death before the end of an offering period, I hereby designate as my beneficiary(ies) to receive all payments and shares due me under the Plan:

Name: (Please print)
	First	Middle	Last
Relationship	Address
	City	State	Zip Code
Name: (Please print)
	First	Middle	Last
Relationship	Address
	City	State	Zip Code
Date:
		Signature of Employee

ELECTION NOT TO PARTICIPATE

     I hereby acknowledge receipt of a copy of Tekelec’s most recent Prospectus which describes the Tekelec 2005 Employee Stock Purchase Plan and elect not to participate in the Plan. I understand that my decision not to participate in the next offering under the Plan will not affect my eligibility to participate in subsequent offerings under the Plan.

Date:
	Signature of Employee

(To be completed by Tekelec)

Date Received: Approved by:

TEKELEC

2005 EMPLOYEE STOCK PURCHASE PLAN

FORM OF

PAYROLL DEDUCTION AUTHORIZATION CHANGE OR WITHDRAWAL

        I am now a participant in the Tekelec 2005 Employee Stock Purchase Plan (the “Plan”) and I wish to make the change indicated below (check one):

o A. Change in Payroll Deduction Rate: I hereby authorize the following new rate of payroll deduction, effective as of the first payday of the next Purchase Period (such change must be filed with the Company at least three days prior to the start of the Purchase Period with respect to which it is to be effective):

(circle one)	1	%	2	%	3	%	4	%	5	%	6	%		7	%	8	%	9	%
	10	%	11	%	12	%	13	%	14	%	15	%	of compensation

o B. Withdrawal from Plan and Immediate Cancellation of Option: I hereby elect to cancel my participation in the Plan effective immediately and to cancel my option to purchase Tekelec Common Stock under the Plan and request that all amounts withheld from me through payroll deductions relating to the canceled option be refunded to me. I understand that cancellation of my option will be effective only if this form is filed with the Company prior to the close of the current Purchase Period. I understand that if I wish to participate in the Plan following my cancellation and withdrawal from the Plan, I must re-enroll by filing a new Subscription Agreement with the Company at least three business days prior to the start of the Offering Period with respect to which it is to be effective.

o C. Withdrawal from Plan without Cancellation of Option in Current Purchase Period. I hereby elect to cancel my participation in the Plan effective as of the first day of the next Purchase Period. However, I request that my previously authorized payroll deductions continue through the end of the current Purchase Period and that all amounts deducted from my Compensation during the current Purchase Period be applied to the purchase of Tekelec Common Stock pursuant to the Plan. I understand that if I wish to participate in the Plan following my cancellation and withdrawal from the Plan, I must re-enroll by filing a new Subscription Agreement with the Company at least three business days prior to the start of the Offering Period with respect to which it is to be effective.

Date:
		Signature of Employee
	Print Name:

(To be completed by Tekelec)

Date Received: Approved by:

EX-5.1

EXHIBIT 5.1

Bryan Cave LLP
120 Broadway, Suite 300
Santa Monica, CA 90401-2386
Telephone: (310) 576-2100
Facsimile: (310) 576-2200

May 23, 2005

Tekelec
26580 West Agoura Road
Calabasas, California 91302

Re: Tekelec — Registration Statement on Form S-8

Ladies and Gentlemen:

          We have acted as securities counsel for Tekelec, a California corporation (the “Company”), in connection with the preparation of a registration statement on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), to be filed with the Securities and Exchange Commission (the “Commission”) on May 23, 2005 in connection with the registration under the Act of an aggregate of 2,500,000 shares of Common Stock, without par value, of the Company (collectively, the “Shares”) consisting of (i) 1,500,000 shares of Common Stock issuable upon exercise of options granted or to be granted pursuant to the Company’s 2004 Equity Incentive Plan for New Employees and (ii) 1,000,000 shares of Common Stock issuable upon exercise of options to be granted pursuant to the Tekelec 2005 Employee Stock Purchase Plan (such plans are referred to herein as the “Plans”).

          In connection with the preparation of the Registration Statement, we have made certain legal and factual examinations and inquiries and examined, among other things, such documents, records, instruments, agreements, certificates and matters as we have considered appropriate and necessary for the rendering of this opinion. We have assumed for the purpose of this opinion the authenticity of all documents submitted to us as originals and the conformity with the originals of all documents submitted to us as copies, and the genuineness of the signatures thereon. As to various questions of fact material to this opinion, we have, when relevant facts were not independently established, relied, to the extent deemed proper by us, upon certificates and statements of officers and representatives of the Company.

          Based on the foregoing and in reliance thereon and upon our review of applicable statutes and case law, it is our opinion that: (i) the Shares have been duly authorized and (ii) the Shares, after the Registration Statement becomes effective and after any post-effective amendment required by law is duly completed, filed and becomes effective, and when the applicable provisions of “Blue Sky” and other state securities laws shall have been complied with, and when the Shares are

issued and sold in accordance with the Plans and the Form S-8 prospectuses to be delivered to the holders of the options, will be validly issued, fully paid and non-assessable.

          We hereby consent to the inclusion of our opinion as Exhibit 5.1 to the Registration Statement and further consent to the reference to this firm in the Registration Statement. In giving this consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

          This opinion is rendered solely for your benefit in accordance with the subject transaction and is not to be otherwise used, circulated, quoted or referred to without our prior written consent. We are opining herein as to the effect on the subject transaction only of United States federal law and the internal (and not the conflict of law) laws of the State of California, and we assume no responsibility as to the applicability thereto, or the effect thereon, of the laws of any other jurisdiction.

Very truly yours,

/s/ BRYAN CAVE LLP

EX-23.1

EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of our report dated March 29, 2005 relating to the consolidated financial statements, financial statement schedule, management’s assessment of internal control over financial reporting, and the effectiveness of internal control over financial reporting, of Tekelec, which appears in Tekelec’s Annual Report on Form 10-K for the year ended December 31, 2004.

/s/ PricewaterhouseCoopers LLP

Los Angeles, California
May 20, 2005