Dissemination of carbapenem resistant GNB (CRGNB) is a major public health concern. Rapid identification of carbapenemase producing GNB is necessary to initiate proper antibiotic regimen and also to prevent dissemination of antibiotic resistance. Although genotypic detection tests remain the gold standard for carbapenemase, their costs in a resource poor laboratory limits its use. In this study, the rapidity, sensitivity and specificity, positive predictive value and negative predictive value of phenotypic methods were compared to genotypic methods to detect carbapenemase in 539 CRGNB. The sensitivity of Combined disk synergy test (CDST) by using EDTA, Double Disc Synergy Test (DDST) + EDTA, MBL E – test, mCIM (Modified Carbapenemase Inactivation Method), Rapidec Carba was 70.28%, 74.06%, 76.07%, 86.15%, 89.17% respectively and specificity was 90.85%, 81.69%, 90.14%, 97.89%, 100% respectively. AmpC hyper producer were 24 (16.90%) among 142 non–carbapenemase producing CRGNB. The sensitivity of ESBL production was 69.57% with ceftazidime plus clavulanic acid (CAZ–CA) and coproduction of ESBL and carbapenemase was 53.06%.