Sanofi Pasteur Supports Polio Eradication at First International Stock Exchange Event

Sanofi Pasteur Stands Shoulder to Shoulder With Rotary International During NYSE and EURONEXT Bell-ringing Ceremonies

LYON, France and SWIFTWATER, Pennsylvania, February 23, 2011 - Sanofi Pasteur, the vaccines division of sanofi-aventis Group
(EURONEXT: SAN and NYSE: SNY), today will participate in the first
international bell-ringing event by a company listed on NYSE Euronext. The
events will acknowledge past successes and future challenges in the battle to
eradicate polio at the stock exchanges in New York, Paris, Brussels,
Amsterdam and Lisbon.

"Sanofi Pasteur stands shoulder to shoulder with Rotary
International, the World Health Organization, the Bill and Melinda Gates
Foundation and the myriad of other organizations that are engaged in this
critical effort to save lives," said Olivier Charmeil, President and CEO of
Sanofi Pasteur. "Protecting and improving human health worldwide is the main
mission of Sanofi Pasteur. As a pioneer and leader in the development of
polio vaccine the company stands behind all efforts that will eradicate the
disease."

Sanofi Pasteur has been supporting the Global Polio
Eradication Initiative (GPEI) since its launch in 1988. GPEI's spearheading
partners are Rotary International, the World Health Organization (WHO), the
U.S. Centers for Disease Control and Prevention (CDC), and UNICEF. Since that
time, Sanofi Pasteur has provided more than 5 billion doses of polio vaccine.
Between 1997 and 2005, Sanofi Pasteur donated over 120 million doses for
polio eradication to respond to emergency situations in African countries
affected by conflicts. In response to an outbreak in Egypt and a request from
WHO, the company developed the first monovalent oral polio vaccine, which
helped in declaring Egypt polio free in 2006.

Recently, Sanofi Pasteur responded to a UNICEF request by
committing to provide 400 million doses of polio vaccine in 2011-2012 for use
in developing countries. The company has also developed specially formulated
polio vaccines to target specific regions. While the standard oral polio
vaccine (OPV) contains three virus strains, Sanofi Pasteur also supplies
formulations containing one or two strains for specific situations. In
addition to producing multiple formulations of OPV, the company is a leading
supplier of inactivated polio vaccine (IPV), which is available as a
single-disease (polio) prevention vaccine as well as in various pediatric
combination vaccines to help protect against other diseases.

About sanofi-aventis

Sanofi-aventis, a leading global pharmaceutical company,
discovers, develops and distributes therapeutic solutions to improve the
lives of everyone. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in
New York (NYSE: SNY). For more information, please visit:
www.sanofi-aventis.com

Sanofi Pasteur, the vaccines division of sanofi-aventis Group,
provides more than 1 billion doses of vaccine each year, making it possible
to immunize more than 500 million people across the globe. A world leader in
the vaccine industry, Sanofi Pasteur offers the broadest range of vaccines
protecting against 20 infectious diseases. The company's heritage, to create
vaccines that protect life, dates back more than a century. Sanofi Pasteur is
the largest company entirely dedicated to vaccines. Every day, the company
invests more than EUR 1 million in research and development. For more
information, please visit: www.sanofipasteur.com or
www.sanofipasteur.us

Forward Looking Statements

This press release contains forward-looking statements as
defined in the Private Securities Litigation Reform Act of 1995, as amended.
Forward-looking statements are statements that are not historical facts.
These statements include projections and estimates and their underlying
assumptions, statements regarding plans, objectives, intentions and
expectations with respect to future financial results, events, operations,
services, product development and potential and statements regarding future
performance. Forward-looking statements are generally identified by the words
"expects," "anticipates," "believes," "intends," "estimates," "plans" and
similar expressions. Although sanofi-aventis' management believes that the
expectations reflected in such forward-looking statements are reasonable,
investors are cautioned that forward-looking information and statements are
subject to various risks and uncertainties, many of which are difficult to
predict and generally beyond the control of sanofi-aventis, that could cause
actual results and developments to differ materially from those expressed in,
or implied or projected by, the forward-looking information and statements.
These risks and uncertainties include among other things, the uncertainties
inherent in research and development, future clinical data and analysis,
including post marketing, decisions by regulatory authorities, such as the
FDA or the EMA, regarding whether and when to approve any drug, device or
biological application that may be filed for any such product candidates as
well as their decisions regarding labelling and other matters that could
affect the availability or commercial potential of such products candidates,
the absence of guarantee that the products candidates if approved will be
commercially successful, the future approval and commercial success of
therapeutic alternatives, the Group's ability to benefit from external growth
opportunities as well as those discussed or identified in the public filings
with the SEC and the AMF made by sanofi-aventis, including those listed under
"Risk Factors" and "Cautionary Statement Regarding Forward-Looking
Statements" in sanofi-aventis' annual report on Form 20-F for the year ended
December 31, 2009. Other than as required by applicable law, sanofi-aventis
does not undertake any obligation to update or revise any forward-looking
information or statements.

www.sanofipasteur.us

Contacts: Global Media Relations, Pascal Barollier, T. +33-(0)4-37-37-50-38, pascal.barollier at sanofipasteur.com; US Media Relations, Len Lavenda, T. +1-570-957-0717, len.lavenda at sanofipasteur.com