The resistance to beta-lactams in enterococci may be related to not only the changes in penicillin-binding proteins but also the production of beta-lactamase. The production of beta-lactamase may lead to the loss of synergistic effect between penicillins and aminoglycosides. It was detected that the penicillinase activity of the enterococci has been carried out by a plasmid which has responsible for the high level aminoglycoside resistance. It was detected that the penicillinase activity of the enterococci has been carried out by a plasmid which was responsible for the high level gentamicin resistance (HLAR). The aim of our study was to investigate the production of beta-lactamase in enterococci and the relationship of high level aminoglycoside resistance with beta-lactamase production. For this purpose 163 rectal swabs of patients from Ataturk University Resea rch Hospital were included in this study. Genus and species determination of the bacteria was done by traditional methods and API 20 Strep commercial test. HLAR was investigated by standard agar screening method. Nitrocephin identification stick was used in the investigation of beta-lactamase production. Enterococci were isolated in 116 of 163 rectal swabs. Of these strains, 67 were identified as Enterococcus faecalis, 45 as Enterococcus faecium, three as Enterococcus casseliflavus and one was Enterococcus avium. HLAR was found in 25.9% of the strains for gentamicin and in 34.5% of the strains for streptomycin. Beta-lactamase producing enterococci strain was not detected in strains with or without HLAR.