Lipase from Aeromonas sobria LP004, isolated from raw milk, was purified and characterized. The lipase was purified 10.29 fold to a homogeneous state by ultrafiltration and column chromatography on phenyl sepharose. The molecular weight of the lipase determined by SDS-PAGE was 97 kDa. Purified A. sobria LP004 lipase exhibited the maximum activity at pH 6.0 and 45 degrees C and was stable under alkaline conditions (pH 6.5-10.0) and at temperatures lower than 40 degrees C. This lipase could be classified as a 1,3-position specific enzyme and its catalytic activity was calcium dependent. PMSF, a serine enzyme inhibitor and 2-mercaptoethanol, a reducing agent, did not affect the enzyme activity.