A study was conducted to determine the influence of pH and temperature on endogenous phytases activity and to investigate the influence of pH and temperature of soaking on hydrolysis of inositol hexaphosphate in lentil, pea, and faba bean seeds. In the first experiment, the sodium phytate was hydrolyzed by phytase extracted from the germinated seeds and the released inorganic phosphorus was measured. Second experiment relied on measuring the changes in seed contents of inositol phosphates as affected by soaking-activated phytases at 37^oC, 45^oC and 55oC and pH 4.0, 5.0, 6.4, 7.0 and 8.0. In both experiments, the highest activities of endogenous phytase were found in pH 5.0 for lentil, pH 4.0 for faba bean and pH 7.0 for pea, and the temperature of 45oC appeared to be the most suitable for enzyme activity, for all examined species. The obtained results, proved by two experiments, can indicate that above mentioned pHs and temperatures are convenient for optimal activity of phytase enzyme in examined seeds, what can be used in the technology of fodder and food production.