Carbapenem group of antibiotics play a vital role in the management of hospital-acquired gram negative infections, because of their broad spectrum activity and stability to hydrolysis by most of the β-lactamases, including extended spectrum β-lactamases (ESBLs). Nosocomial outbreaks of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. due to metallo-β-lactamases (MBLs) production have been reported from different regions. [1],[2],[3] The emergence of these MBLs in gram negative bacilli is becoming a therapeutic challenge as these enzymes possess high hydrolytic activity that leads to degradation of higher generation cephalosporins. Moreover, the treatment alternatives are unavailable, or expensive/toxic with poor outcome. [4] Plasmid mediated MBL genes spread rapidly to other species of gram negative bacilli; [5] therefore rapid detection of metallo-β-lactamases production is necessary to modify therapy and to initiate effective infection control to prevent their dissemination. To date there has been one report from Pakistan suggesting presence of MBL producing isolate. [6] There is however need for a systematic study to assess the extent of this form of resistance amongst our isolates. The purpose of this study was to evaluate the metallo-β-lactamase (MBL) production among multidrug resistant (MDR) Acinetobacter spp. and Pseudomonas aeruginosa , isolated from clinical specimens of intensive care unit patients.