The trematode Calicophoron erschowi possesses high active phosphoenolpyruvate carboxykinase. Enzyme activity is concentrated in the cytoplasm. The enzyme has the optimum pH 6.0 and is active in the presence of ions Mn++ and inosine diphosphate. Alanine does not affect its activity. Sulphide oxinide in concentration 1.4-10(-6) M inhibits the activity up to 93%. Some kinetic characteristics are presented.