A procedure was developed for the extraction of rennet from fresh frozen vells. Frozen vells were minced in a Model VCM-25 Hobart Vertical Cutter/Mixer. Dry sodium chloride was added until the salt concentration in the moisture of the tissue was 10%. Salted tissue was placed in galvanized steel cells and heated in a water bath to 49, 54, 57 and 60 C for 0, 15, 30, 45 and 60 minutes. The heated tissue was dried to about 4% moisture at ambient temperature with the aid of an electric fan. The dried salted tissue was extracted with a sodium chloride solution adjusted to give a salt concentration of 10% in the extraction solution. Salted vell tissue heated to 49 C for 60 minutes and to 54 C for 30 minutes prior to drying produced 82 and 55%, respectively, more recoverable enzyme activity than unheated salted tissue. However, tissue which was salted, heated and not dried prior to extraction produced less recoverable activity than unheated samples. Unsalted vell tissue which was heated to 49, 54, 57 and 60 C for 15, 30, 45 and 60 minutes and extracted without being dried yielded lower recoverable activity than unheated samples. Heating unsalted vell tissue to 54, 57 and 60 C for 15, 30, 45 and 60 minutes prior to drying did not increase recoverable enzyme activity over unheated samples. Unsalted tissue heated to 49 C produced a slightly higher recovery than unheated samples.