Histopathological, histochemical and immunohistochemical studies were carried out on the skeletal muscles of mice experimentally infected with Schistosoma mansoni throughout 20 weeks post infection. Histopathogical changes were detected from the 13th week post infection inspite of absence of Schistosoma mansoni eggs. There were definite enzymatic changes dehydrogenase, non specific esterase and acid and alkaline phosphatases. These changes started from the 14th week post infection. S. mansoni immune complex deposits were detected in the muscles from the 9th week post infection. Positive correlation was found between the degree of immune complex deposition and histopathological and histochemical changes. The study confirmed the role of immune complex in the pathogenesis of skeletal muscle lesion in Schistosoma mansoni infection (schistosomal myopathy).