Chairman & CEO of Sigma-Aldrich Corporation
Rings The NASDAQ Stock Market Opening Bell

Thursday, August 11, 2005
at NASDAQ's MarketSite
in New York City.

Sigma-Aldrich Corporation

David Harvey, Chairman & CEO of Sigma-Aldrich Corporation (NASDAQ: SIAL) N-100, presides over the opening bell to celebrate its 30-year anniversary on the NASDAQ.

Sigma-Aldrich Corporation (NASDAQ: SIAL), a leading $1.4 billion Life Science and High Technology company headquartered in St. Louis, Mo., has experienced above-market revenue growth, continued dividend increases and 15% compound annual growth in its stock price over its 30-year history

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