Seventy-nine strains of Acinetobacter baumannii isolated from pathologic products obtained mainly from surgical and intensive care units at the Rabta Hospital in Tunisia were studied. The sensitivity of these bacteria to the antibiotics used singly or in combination was tested in order to determine the most effective agents. Sensitivity to the disinfectants routinely used in our hospital was also studied using the "dilution-neutralisation" method according to "AFNOR" norms in order to identify the product with the most powerful preventive effect for Acinetobacter baumannii infection. The bacteria tested were resistant to all antibiotics except imipernem, colistin, and some aminoglycosides. A combination of imipenem-amikacin was effective against all strains. Best disinfection was obtained after 5 minutes of bacterial contact with aldehyde, phenol and amphotere.