Using histochemical and cytophotometric methods, enzymes responsible for the membrane transport (alkaline phosphatase, adenosine triphosphatase, and 5-nucleotidase) in the developing sporocyst of Fasciola hepatica (L., 1758) were studied. The most active metabolism occurred in the germ balls of sporocysts on the 8th and 15th days of development, which is associated with intensive proliferation and subsequently differentiation of embryos within the germ balls.