Microbix Biosystems Inc. Closes Previously Announced Equity Offering for Gross Proceeds of $448,231

TORONTO, December 5, 2011 /CNW/ – Microbix Biosystems Inc. (“Microbix” or the “Company”) (TSX:MBX) has closed its previously announced public offering of Units. A total of 2,241,158 Units were sold at a price of $0.20 per Unit, for gross proceeds of $448,231. Each Unit consists of: one common share in the share capital of Microbix; one half of one common share purchase warrant entitling the holder to purchase one additional Common Share with an exercise price of $0.25 for a period of five years from the date of closing; and one common share purchase warrant entitling the holder to purchase one additional Common Share with an exercise price of $0.24 for a period of three years after the date of closing of the offering.

The Unit offering has been completed in the provinces of Ontario, British Columbia and Alberta pursuant to a Prospectus Supplement dated November 28, 2011 to the Company’s Short Form Base Shelf Prospectus dated October 7, 2011. Euro Pacific Canada Inc. acted as Agent and Bloom Burton & Co. acted as a selling firm. The Agent was paid a commission of 7% of the gross proceeds of the Offering and granted Compensation Options to purchase up to 7% of the number of Units sold under the offering. Each Compensation Option entitles the holder to purchase one Unit for a period of 2 years from the date of closing.

Net proceeds of the offering will be used for Microbix’ research and development initiatives including, but not limited to, its semen-sexing product, LumiSort TM.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy any securities of the Company in any jurisdiction in which such offer, solicitation or sale would be unlawful. The securities to be offered have not been and will not be registered under the United States Securities Act of 1933, as amended, or any state securities laws, and may not be offered or sold within the United States absent registration or an applicable exemption from the registration requirements of the United States Securities Act of 1933, as amended, and applicable state securities laws.

For further information: visit www.microbix.com or contact:

William J. Gastle CEO

Microbix Biosystems Inc.

416-234-1624 x 230 4

James Long CFO

Microbix Biosystems Inc.

416-234-1624 x 265