Via Facsimile and U.S. Mail
Mail Stop 6010
								August 26, 2005

Mr. Weidong Yin
President, Chief Executive Officer and Director
Sinovac Biotech Ltd.
39 Shangdi Xi Road
Haidian District
Beijing, P.R.C.  100085

Re:	Sinovac Biotech Ltd.
	Form 20-F for Fiscal Year Ended December 31, 2004
	File No. 1-32371

Dear Mr. Yin:

      We have limited our review of your filing to those issues we
have addressed in our comments.  Where indicated, we think you
should
revise your document in response to these comments.  If you
disagree,
we will consider your explanation as to why our comment is
inapplicable or a revision is unnecessary.  Please be as detailed
as
necessary in your explanation.  In some of our comments, we ask
you
to provide us with more information so we may better understand
your
disclosure.

	Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your
filings.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or any other aspect
of
our review.  Feel free to call us at the telephone numbers listed
at
the end of this letter.

Form 20-F for the year ended December 31, 2004

Item 5: Operating and Financial Review and Prospects, page 31

1. Please revise your filing to include the tabular disclosure of
contractual obligations required by Item 5F of Form 20-F or tell
us
why this disclosure is not required.
2. It appears that certain accounting estimates or assumptions
have a
material impact on your financial statements.  Please revise your
disclosure to include a discussion of your critical accounting
estimates as outlined in Section V of Financial Reporting Release
No.
72 or explain to us why you believe you have no critical
accounting
estimates or assumptions.

Item 11: Quantitative and Qualitative Disclosures About Market
Risk,
page 60
3. You indicate that your Chinese operations may give rise to
significant foreign currency exchange risks between the US dollar
and
the Chinese RMB.  Please revise your disclosure to provide the
quantitative disclosures about market risk using one of the three
disclosure alternatives required by Item 11(a) of Form 20-F or
tell
us why this disclosure is not required.

Item 17: Financial Statements, page 65

Consolidated Statements of Operations, page 70
4. It appears from your disclosure of depreciation and
amortization
that the amortization of licenses and permits related to products
sold is not classified in costs of sales.  Please explain to us if
amortization of intangibles related to products sold is included
in
cost of sales.  If not, please revise your disclosure to
reclassify
the appropriate amounts to cost of sales.  Alternatively, expand
the
cost of sales caption to include parenthetical disclosure
indicating
that amortization of intangible assets related to products sold is
excluded and disclose the amount of amortization excluded from
cost
of sales.  Please refer to SAB Topic 11:B.  In addition, please
modify your gross profit analysis in Item 5 to disclose the gross
profit amounts including amortization.
5. Please reclassify your interest and financing expenses to group
them with non-operating income and expenses as indicated in Rule
5-03
of Regulation S-X or tell us why interest and financing expenses
are
considered operating expenses.

Notes to Consolidated Financial Statements, page 72

Note 1: Nature of Business, page 72
6. You indicate that you reflected the acquisition of Net-Force as
a
capital reorganization of Sinovac China as the shareholders of
Sinovac China controlled Net-Force after the acquisition.
However,
it appears that the pre-acquisition shareholders of Sinovac China
hold only 10,000,000 shares of the combined 27,091,033 shares
outstanding immediately after the transaction, or 37% of the
combined
entity.  Please explain to us how the Sinovac China shareholders
control the combined entity as a result of the transaction and why
you believe accounting for the acquisition as a reorganization is
appropriate under GAAP.  In your response, please also tell us the
extent that shareholders and management of Net-Force prior to the
transaction have been involved in managing the company after the
transaction. Further, provide us your accounting analysis
demonstrating how your accounting for minority interest (i.e. the
49%
interest in Sinovac China that was not acquired September 24,
2003)
complies with US GAAP and how you determined the amount of
minority
interest as of each balance sheet date and for each period in the
statements of operations.  Please ensure that you reference all
applicable accounting guidance in your response.

7. Please refer to your recapitalization line items in your 2002
and
2003 consolidated statements of stockholders` equity.  Please tell
us
the nature of each recapitalization line item disclosed and
provide
us an explanation as to why there are no shares reflected as
issued
or outstanding in 2002.  In addition, please tell us how you
determined the weighted-average number of shares outstanding
reflected in your 2002 and 2003 consolidated statements of
operations.

Note 7: Licenses and Permits, page 82
8. Please explain to us the nature of the costs related to the
licenses and permits for your inactive hepatitis A vaccine.  Tell
us
whether the amounts are internal costs or amounts paid to a third
party.
9. You indicate that you capitalized costs for your recombinant
hepatitis A&B vaccine and your influenza virus HA vaccine prior to
receipt of marketing approval from the SFDA.  Please provide us an
explanation of how these licenses and permits have alternative
future
uses under paragraph 11c of SFAS 2.  If these licenses have
alternative uses, please explain to us the literature relied upon
for
deferring amortization until you start drug production.

Note 9: Income Taxes, page 84
10. You recorded an income tax benefit for the first time in 2004.
Given your history of operating losses, please explain to us how
you
concluded that it is more likely than not that you will realize
the
deferred tax asset recorded at December 31, 2004.  In your
response,
please specifically address the factors identified in paragraphs
23
and 24 of SFAS 109, and a discussion of the new evidence you
considered in 2004 to support your conclusion that a full
valuation
allowance was not needed.

      As appropriate, please amend your Form 20-F for the year
ended
December 31, 2004 and respond to these comments within 10 business
days or tell us when you will respond.  You may wish to provide us
with marked copies of the amendment to expedite our review.
Please
furnish a cover letter with your amendment that keys your
responses
to our comments and provides any requested information.  Detailed
cover letters greatly facilitate our review.  Please file the
letter
on EDGAR under the form type label CORRESP.  Please understand
that
we may have additional comments after reviewing your amendment and
responses to our comments.

      We urge all persons who are responsible for the accuracy and
adequacy of the disclosure in the filing to be certain that the
filing includes all information required under the Securities
Exchange Act of 1934 and that they have provided all information
investors require for an informed investment decision.  Since the
company and its management are in possession of all facts relating
to
a company`s disclosure, they are responsible for the accuracy and
adequacy of the disclosures they have made.

	In connection with responding to our comments, please
provide,
in your letter, a statement from the company acknowledging that:

* the company is responsible for the adequacy and accuracy of the
disclosure in the filing;

* staff comments or changes to disclosure in response to staff
comments do not foreclose the Commission from taking any action
with
respect to the filing; and

* the company may not assert staff comments as a defense in any
proceeding initiated by the Commission or any person under the
federal securities laws of the United States.

      In addition, please be advised that the Division of
Enforcement
has access to all information you provide to the staff of the
Division of Corporation Finance in our review of your filing or in
response to our comments on your filing.

	If you have any questions, please contact Mark Brunhofer,
Staff
Accountant, at (202) 551-3638 or Donald Abbott, Senior Staff
Accountant, at (202) 551-3608.  In this regard, do not hesitate to
contact me, at (202) 551-3679.

Sincerely,



Jim B. Rosenberg
Senior Assistant Chief Accountant
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Mr. Weidong Yin
Sinovac Biotech Ltd.
August 26, 2005
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