Via Facsimile and U.S. Mail
Mail Stop 6010
								October 12, 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/A for Fiscal Year Ended December 31, 2004
	Filed September 21, 2005
      File No. 1-32371

Dear Mr. Yin:

      We have reviewed your amendment and response letter dated
September 21, 2005 to our comment letter dated September 12, 2005
and
have the following 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 filing.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or on 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 Amendment No. 2 for the year ended December 31, 2004

Item 17: Financial Statements, page 69

Consolidated Statements of Operations, page 74

1. We acknowledge your response to our previous comment four.
Please
revise your interest and financing expenses to reflect all amounts
presented as negative numbers.  It appears that the amount for
2002
is properly reflected as a negative number, but your 2003 and 2004
amounts appear as positive numbers.

Note 1: Nature of Business, page 76

2. We acknowledge your responses to our previous comments six and
seven.  The financial statements you present related to the
periods
before the reverse acquisition transaction reflect the entire
operating results of Sinovac Beijing, yet reflect only the shares
related to the majority interest, the 10,000,000 shares, after the
transaction.  As a result, please address the following:
a. As requested in our previous comment six, please revise your
statements of stockholders` equity and your footnote disclosure to
reflect the equivalent of all restated shares of Sinovac Beijing,
or
19,607,843 shares, outstanding immediately before the reverse
acquisition transaction.
b. In conjunction with the reverse acquisition transaction, please
reflect an effective spin-off of the 9,607,843 shares that
represent
the minority interest created in the transaction.
c. As requested in our previous comment seven, please revise your
loss per share for 2002 through the reverse acquisition
transaction
in 2003 to reflect weighted average shares outstanding for the
Sinovac Beijing shares on a 100% basis rather than a 51% basis,
and
from the reverse acquisition date through December 31, 2003 to
reflect the effective spin-off of the minority interest in
conjunction with the transaction.  Please provide us with your
revised 2002 and 2003 weighted-average share computations.

Note 7: Licenses and Permits, page 84

3. Please file your email correspondence dated September 28, 2005
and
October 3, 2005 on EDGAR under the form type label CORRESP.

4. It appears that the ultimate value of any pharmaceutical in
China
is dependent upon the receipt of all four regulatory approvals
from
the SFDA.  We also acknowledge from your email correspondence
dated
October 3, 2005 that the receipt of a new drug certificate, the
second of the four regulatory approvals,  appears to be
representative of an asset under CON 6 and have separate economic
value under paragraph 11c of SFAS 2 as it may be sold or licensed.
However, we do not believe that the receipt of the approval to
commence clinical trials, the first of the four regulatory
approvals,
for any individual condition is indicative of an alternative
future
use under paragraph 11c of SFAS 2.  As the only approval received
on
the dates you acquired the Hepatitis A&B and Influenza vaccines
was
the approval to conduct clinical trials, we believe these
transactions represent the purchase of in-process research and
development.  Unless you can demonstrate to us that these projects
had alternative future uses in research and development projects
or
otherwise, please revise your financial statements and disclosure
throughout your documents to charge the purchase prices of your
Hepatitis A&B and Influenza vaccines to research and development
expenses upon acquisition.


5. We acknowledge your response regarding the Hepatitis A vaccine
in
both your September 28, 2005 and October 3, 2005 email
correspondence
and in your response to our previous comment nine related to your
Hepatitis A&B and Influenza vaccines.  We continue to have
concerns
about your delay in beginning to amortize your licenses and
permits
until production commenced.  It appears that separate economic
value
existed upon the acquisition of your Hepatitis A vaccine as the
new
drug certificate was already issued.  Also it appears that the
construction of the manufacturing facility caused the delay in the
issuance of the production license and the GMP certificate.
Please
tell us in detail the timing of the events surrounding the
remaining
approvals for the Hepatitis A vaccine.  In your response, please
indicate the steps you took and the costs incurred to obtain the
production license and the GMP certificate and the uncertainties
surrounding ultimate approval.  Please elaborate on why it took
over
two years from the receipt of the new drug certificate to receive
the
production license when , in your October 3, 2005 email
correspondence, you indicate that obtaining a production license
is
straightforward.  Please assess the probability of whether the
receipt of a production license is likely to occur after receiving
the new drug certificate and the basis for your assessment.  Also
in
your response, please specifically indicate whether you could have
received the production license and GMP certificates sooner if,
for
example, you engaged a contract manufacturer to produce the
vaccine.
Please tell us whether the delays in receiving the production
license
and the GMP certificate were solely related to the decision to
build
your own manufacturing facility.

Note 9:  Income Taxes, page 88

6. Consistent with your response to our previous comment 10,
please
revise your disclosure to specifically discuss the facts and
circumstance that occurred in 2004 that resulted in management
concluding that a 100% valuation allowance was not needed.  In
your
disclosure, please indicate that you anticipate future taxable
income
for Sinovac Beijing and the nature of your available tax planning
strategies.  In addition, please consider expanding Item 5 of your
Form 20-F to disclose deferred income tax valuation allowance as a
critical accounting estimate.

      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.

      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


cc:	Mr. Michael T. Shannon, Esq.
	Devlin & Jensen

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Mr. Weidong Yin
Sinovac Biotech Ltd.
October 12, 2005
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