Öz Susceptibilities of eight strains of aerobic, oxalate-utilizing bacteria and two oxalate-utilizing reference strains Pseudomonas oxalaticus DSM 1105 and Methylobacterium extorquens DSM 1337 to 18 antimicrobial agents were determined by the National Conunittee for Clinical Laboratory Standarts (NCCLS) disk diffusion method. Ali strains were sensitive towards Carbenicillin and resistant to Rifampicin. Penicillinase production was detected in 80% of ali strains tested. The results show that in addition to the normal determination methods it is possible to separate some of the strains of these oxalate utilisers with the help of antimicrobial susceptibility patterns.