Abstract 1. 1. The electrophoretic separation is described for acid phosphatase, non-specific esterase, leucine amino peptidase, lactase, malate, α-glutamate, glucose-6-phosphate and 6-phosphogluconate dehydrogenases from adults of four populations of Schistosoma mansoni and one population of S. haematobium. 2. 2. The patterns are compared between sexes, between adults and cercariae, and between species. 3. 3. In S. mansoni differences between sexes were found for esterase, lactate, malate and glucose-6-phosphate dehydrogenases, and between esterase and lactate dehydrogenase in S. haematobium. 4. 4. Clear qualitative differences between species were found with esterase, and lactate and glucose-6-phosphate dehydrogenase isoenzymes.