Etiologies of infectious diarrhoeas in hospitalised adults have been studied during one year; research of cryptosporidium and isospora oocysts is being made with Henriksen-Pohlenz and Kato methods. Diarrhoea is associated with a positive HIV serology in 40% cases. Cryptosporidium spp is found in 38% of cases. In 91% cases of cryptosporidiosis HIV serology is positive. Cryptosporidiosis is the main cause of AIDS diarrhoeas in Mali. 3 cases of isosporiasis are associated with cryptosporidiosis in AIDS patients. Emaciation and dehydration are the main signs of severity. Diarrhoea's profusion, its chronicity and inefficiency of the treatments explain the heavy death rate of cryptosporidiosis among seropositive patients, which reaches 40% during the first two weeks of hospitalisation.