The antimicrobial resistance evolution of the Bacteroïdes fragilis group is the subject of international survey. Eighty-six clinical isolates collected in anaerobic service of I.P. A were tested for susceptibility to twelve antimicrobial agents. Chloramphenicol, metronidazole and imipenem proved to be the most active agents. After these agents, amoxicillin-clavulanic acid, carbenicillin and piperacillin were the most effective agents tested with respectively 15%, 17% and 17% of resistant isolates. Clindamicin and cefotaxin were active from only 70% and 65% of clinical isolates, and 71% of them were found resistant to cefotaxin with minimal inhibitory concentration above 32 ug/ml. beta Lactamasic profile determination according to Rolfe and Finegold modified method allowed to show five different beta lactamase types. The isoelectric points (pI) vary between 4.3 and 7.5 according to the enzymatic extracts of the clinical isolates. No transfer and no plasmid were observed with respectively imipenem and metronidazole resistant isolates. But, transconjugants were obtained with TRCcR isolate.