A bacterial strain, Klebsiella oxytoca MO-3, producing phytase (EC 3.1.3.8) was isolated from compost. The phytase was extracted and purified 400-fold and partially characterized. The pH optimum was found to be in the range of 5-6 and the optimum temperature to be 55 degrees C. The phytase is stable at pH 4-8 and no loss of activity upon its incubation at 60 degrees C for 20 min was detected. The partially purified enzyme was strongly inhibited by NaF, Zn2+, Fe2+, and Cu2+ but not inhibited by EDTA or N-ethylmaleimide.