The growth of a probiotic-strain of Lactobacillus sp. in a bovine blood plasma-based medium and its stability against the freeze-drying process were investigated. Nitrogen sources in a complex (MRS) medium were replaced by the enzymatic hydrolysate of blood plasma using a selected industrial protease. The cell mass produced in the medium under optimum conditions, 5.2 x 10(9) CFU/ml, was significantly high, and about 74% of that in MRS medium. The blood protein hydrolysate in the medium also enhanced the survival rate of the strain against freeze-drying, for which sucrose was selected as the most effective stabilizer.