Abstract—Metallo- ß-lactamase (MBL) producing Acinetobacter species has become a growing therapeutic concern worldwide. Thus, the present study was conducted to determine the prevalence of MBLs in imipenem-nonsusceptible isolates of Acinetobacter species from a teaching tertiary care hospital. During a period of one year (May 2010 to April 2011), 100 isolates of Acinetobacter species were collected from different clinical specimens received in Microbiology laboratory. All isolates were tested for antimicrobial susceptibility by Kirby-Bauer disc diffusion method. Carbapenem nonsusceptible isolates were further processed for detection of MBL production by combined disc test according to Yong et al. Of the 100 Acinetobacter isolates, 82 were identified as A. baumannii and 18 as A. lwoffii . Imipenem nonsusceptible isolates were 70%, out of which 39 (55.7%) isolates showed MBL production. Of 39 MBL positive isolates, thirty four (87.1%) were multi drug resistant. Statistically significant difference was found in the antimicrobial resistance of MBL producing and MBL non producing isolates for ciprofloxacin, amikacin, gentamicin, netilmicin, piperacillin tazobactam and ß -lactam antibiotics ( p value < 0.05).