The extracellular lipase of Staphylococcus warneni was secreted asa protein with an apparent molecular mass of 90 kDa. It was then sequentially processed in the supernatant to a protein of 45 kDa. Tryptic digestion of the crude extract resulted in a homogeneous sample containing only the 45-kDa form. Purification was achieved by hydrophobic chromatography. Purified lipase had an optimum pH of 9.0 and an optimum temperature of 25 degrees C. The enzyme was stable within the range pH 5.0-9.0; it had a broad substrate specificity. The results of inhibition studies were consistent with the view that lipases possess a serine residue at the catalytic site.