Mice were infected with 1000 Schistosoma haematobium cercariae (Egyptian strain). Histopathological and histochemical studies were performed on the different organs, during the first four weeks after infection and on the fourth week after oviposition. Pathological changes during early prepatency matched with those in S. mansoni infection. Eggs were laid in aggregates in the colon and liver. They initiated the development of typical granulomatous lesions. Abundant bilharzial pigment and areas of sclerosis were present in both liver and spleen. The heart, kidneys and urinary bladder were pathologically free. Disturbed succinic dehydrogenase and acid phosphatase enzyme levels were detected which point to a derangement in the functions of the cell organelles.