Using histochemical and cytophotometric methods, enzymes associated with anaerobie glycolysis: glucose-6-phosphatase, hexokinase, and aldolase in the developing sporocysts of Fasciola hepatica were studied. Highest activity of these enzymes was found in the germ balls in the sporocysts, at all phases of their development, which is related to intensive proliferation and differentiation of the embryos developing inside the germ balls