NEWS RELEASE for February 4, 2008

Contact

Allen & Caron Michael Mason (investors) Brian Kennedy (media) 212 691 8087 michaelm@allencaron.com brian@allencaron.com

Jonathan Hunt, CFO 509 375 1202 jhunt@isoray.com

Richland, Washington (February 4, 2008) … IsoRay Inc. (AMEX:ISR), a medical isotope company focused on the treatment of prostate cancer and other malignant disease through use of its proprietary radioisotope technology, announced today it will release second quarter fiscal 2008 results on Monday, February 11, 2008, before market opening. That same day, at 4:30 PM ET, management will host a conference call, which will be broadcast live over the Internet.

Participants should dial into the call 10-15 minutes before the scheduled time using the following numbers: 877-407-8031 (from the US and Canada) or +1 201 689-8031 (from outside the US and Canada). A live webcast of the conference call will also be accessible via the Internet at www.isoray.com, or by going to www.investorcalendar.com.

The telephonic replay of the conference call will be available by dialing 877-660-6853 (from the US and Canada) or +1 201 612-7415 (from outside the US and Canada) and by entering account number 286 and conference ID number 273560. An online archive will also be available immediately following the call at the sites noted above. Both are available for ten days, through February 21, 2008.

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IsoRay, Inc., through its subsidiary, IsoRay Medical, Inc., is the sole producer of the Proxcelan™ Cesium-131 brachytherapy seed, used to treat prostate and other cancers. The Proxcelan™ seed offers a significantly shorter half-life than the two other isotopes commonly used for brachytherapy, which results in a substantially faster delivery of therapeutic radiation, lower probability of cancer cell survival and reduction of the longevity of common brachytherapy side effects (a)(b). IsoRay is based in Richland, Washington. More information is available about IsoRay at www.isoray.com.

a) Armpilia CI, Dale RG, Coles IP, et al. The Determination of Radiobiologically Optimized Half-lives for Radionuclides Used in Permanent Brachytherapy Implants. Int. J. Radiation Oncology Biol. Phys. 2003; 55 (2): 378-385.
(b) Prestidge B.R., Bice W.S., Jurkovic I., et al. Cesium-131 Permanent Prostate Brachytherapy: An Initial Report. Int. J. Radiation Oncology Biol. Phys. 2005; 63 (1): 5336-5337.

Statements in this news release about IsoRay's future expectations, including: the advantages of our Proxcelan™ Cesium-131 seed, whether we will be successful in locating a qualified independent director to serve on the Board in the future, and all other statements in this release, other than historical facts, are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 ("PSLRA"). This statement is included for the express purpose of availing IsoRay, Inc. of the protections of the safe harbor provisions of the PSLRA. It is important to note that actual results and ultimate corporate actions could differ materially from those in such forward-looking statements based on such factors as successful completion of future research and development activities, physician acceptance, training and use of IsoRay's products, IsoRay's ability to successfully manufacture, market and sell its products, IsoRay's ability to manufacture its products in sufficient quantities to meet demand within required delivery time periods while meeting its quality control standards, IsoRay's ability to enforce its intellectual property rights, whether additional studies support the conclusions of early clinical studies, and other risks detailed from time to time in IsoRay's reports filed with the SEC.