American Science and Engineering, Inc. Moves to NASDAQ National Market System.

BILLERICA, Mass. -- AS&E's President and CEO, Anthony Fabiano, to open The NASDAQ Stock Market on its first day of trading October 6, 2004

E[acute accent]American Science and Engineering, Inc. (AMEX:ASE) (AS&E(R)), a leader in X-ray detection technology, announced today that the Company's common stock will begin trading on The NASDAQ National Market on October 6, 2004 under the symbol (NASDAQ: ASEI). Anthony Fabiano, AS&E's President and CEO, will celebrate the Company's NASDAQ National Market listing and first day of trading by opening the market at NASDAQ's MarketSite on Times Square. E[acute accent]"We are honored to open the NASDAQ market on our first day of trading under our new symbol ASEI," said Fabiano. "The move to NASDAQ is an important step to increase the Company's exposure to the investment community and a positive step in our mission to deliver superior growth in shareholder value. The NASDAQ will provide the AS&E investment community with enhanced investor services, improved liquidity and international visibility for the Company's shares. Our investors will benefit from the fast execution and low cost per trade from the largest stock market in the world. We are very proud to be joining the premier stock market for leading-edge technology companies, such as AS&E, and we look forward to many years of success with NASDAQ." E[acute accent]The Company's common stock will trade on The American Stock Exchange under the symbol "ASE" until market close today. E[acute accent]Bruce Aust, Executive Vice President of The NASDAQ Stock Market said, "American Science and Engineering has been a technology leader and innovator in the critical areas of X-ray inspection and defense applications. The NASDAQ Stock Market's philosophy is based on innovation and competition and as a result we are the home of category defining companies such as AS&E. We are thrilled to have them on list on our market and officially welcome them to NASDAQ." For more information on AS&E's opening day at the NASDAQ, please visit http://www.nasdaq.com/reference/marketsite_events.stm.

E[acute accent]About AS&E(R)

E[acute accent]American Science and Engineering, Inc. develops and manufactures state-of-the-art X-ray inspection systems for homeland security and other critical defense applications. AS&E continues to innovate, create and develop new products by investing in new ideas through research and development, and evolving its technology to meet the needs of an ever-changing world. AS&E's patented Z(R) Backscatter technology detects plastic explosives, illegal drugs, and other contraband, even when artfully concealed in complex backgrounds by terrorists and smugglers. AS&E's Shaped Energy(TM) X-ray inspection systems combine the material discrimination features of Z(R) Backscatter imaging with the penetration capability of high-energy X-rays for dense cargoes, without the problems caused by excessive radiation. AS&E's High Energy Systems Division manufactures linear accelerators for a variety of applications including medical, scientific, security, electron beam curing and non-destructive testing. For more information on AS&E products and technologies, please visit http://www.as-e.com.

E[acute accent]Safe Harbor Statement: The foregoing press release contains statements concerning AS&E's financial performance, markets and business operations that may be considered ``forward-looking'' under applicable securities laws. AS&E wishes to caution readers of this press release that actual results might differ materially from those projected in any forward-looking statements. Factors which might cause actual results to differ materially from those projected in the forward-looking statements contained herein include the following: significant reductions or delays in procurements of the Company's systems by the United States and other governments; disruption in the supply of any source component incorporated into AS&E's products; litigation seeking to restrict the use of intellectual property used by the Company; potential product liability claims against the Company; global political trends and events which affect public perception of the threat presented by drugs, explosives and other contraband; global economic developments and the ability of governments and private organizations to fund purchases of the Company's products to address such threats; and the potential insufficiency of Company resources, including human resources, capital, plant and equipment and management systems, to accommodate any future growth, and future delays in federal funding. These and certain other factors which might cause actual results to differ materially from those projected are detailed from time to time in AS&E's periodic reports and registration statements filed with the Securities and Exchange Commission, which important factors are incorporated herein by reference. AS&E undertakes no obligation to update forward looking statements to reflect changed assumptions, the occurrence of unanticipated events, or changes in future operating results, financial condition or business over time.