The ability of two species of Bacillus to degrade child's scalp hair, cow horn, cow hooves, and human nails in vitro under static conditions was studied by the determination of soluble sulphhydryl compounds as cysteine, disulphides as cystine, and release of extracellular keratinase along with changes in alkalinity of the culture filtrate. Child's scalp hair was found to be the most favored keratin substrate for Bacillus spp.