Incidence of Mycobacterium avium complex (MAC) infection has increased in HIV infected patients. We report a retrospective study of 25 cases of MAC infection occurring in HIV patients. Stools examination was performed in 5 (31%) of the patients without digestive symptoms and in the 9 (100%) patients presenting with diarrhoea. The stools culture are positive in 79% of cases (11/14). In all the patients with diarrhoea, direct examination of the stools gave the diagnosis of MAC infection. All the patients had profound immunodepression with CD4+ cell count < 5/mm3. The mean survival time from mycobacteriosis diagnosis was 122 +/- 90 days despite antimycobacteriosis therapy.