Schistosomiasis pathology demonstrates the successive stages of the specific inflammation and accounts for the large variety of its macroscopic and histological features. This paper reviews 286 bilharzial lesions studied between 1956 and 1979 at the ""Institut de Médecine tropicale du Service de santé des Armées". - First, the histopathological caracteristics of the disease are considered. Some lesions are caused by schistosomules and adult worms, but the proeminent role is devoted to egg: the bilharzial granuloma get developped around it, and is the elementary and specific lesion, after three successive phases: exsudative nodule, productive granuloma and scleral nudule. Some recent researches about histogenesis of this granuloma have pointed out the role, in the immune response, of cell mediated cytotoxicity. - The the pathological aspects due to each of the four parasitic species are described: S. haematobium is predominant (249 cases). 34,2 percent of the examined lesions are of vesical and/or ureteral nature. Vesical changes are increased because their chronic evolution and are frequently modified by secondary infections: lesions of uretere, giving stricture, frequently induce severe complications in the upper part of the urinary tract. The different parts of female genital tract (61 specimens) may be affected, with cervix and fallopian tubes more often hit. Testis and epididymis frequently show tumoral features, mainly in young patients. Appendicitis (41 cases) may have various pathological aspects. S. mansoni infections (34 cases) specially affect liver and côlon. Three degrees of inflammation are described in liver where Symmers fibrosis is characteristic. Inflammatory lesions as well as tumors are observed in côlon, rectum and anus. Lesions caused by S. japonicum have been detected in three specimens (liver and appendix). A brief description about S. intercalatum lesions is presented. - The study gives some information regarding the geographical origin of the patients, their age and the polymorphorus features of the lesions. Diagnosis of tumors requests special staining techniques. Completing the parasitologic and immunologic methods, anatomopathology may help diagnosis of bilharziasis. It should be included in any multidisciplinary and long term eradication programme.