From 1982 to 1986, 122 strains of non-typhoid Salmonellae were isolated at the University Hospital of Sfax (Tunisia). Both tests: serotype classification and sensitivity have demonstrated that the most frequent serotypes: S. wien and S. typhimurium have the highest degree of multiresistance. Ampicillin, cotrimoxazole and chloramphenicol are the most affected while cefotaxime, amikacin and colistin are still saved. Facing these facts, the authors insist on the seriousness of the excessive use of antibiotherapy which leads to the selection of such strains.