AbstractIntroducion: Acinetobacter is a heterogeneous group of gram negative, oxidase negative, non-motile, nonfermenters emerged as an important nosocomial pathogen causing outbreaks of hospital infections. The high prevalence of multidrug resistant isolates makes initiation of effective empiric treatment challenging. Objective: This study was undertaken to isolate and characterise Acinetobacter species in various clinical specimens and to analyse the antibiotic susceptibility pattern. Materials and Methods: A total of 5395 clinical specimens were processed in the department of microbiology of a tertiary care hospital over the period of 2 years. Out of which 147 isolates were Acinetobacter species. Speciation and antibiotic susceptibility was determined by the standard conventional method. ESBL and MBL production was detected by disc potentiation test method and imipenem EDTA combined disc test, and MBL E-test respectively. Results: Prevalence was 2.72%. Most predominant species was Acinetobacter baumannii 128 (87.07%). Maximum isolataion was seen among ICU patients (31.97%). Most of strains were resistant to ciprofloxacin (87.5%), ceftazidime (85.94%). All strains were resistant to piperacillin (100%) and sensitive to colistin and polymyxin B. ESBL, MBL production and MDR was detected in 34.01%, 21.77% and 53.06% of the isolates respectively. Discussion and Conclusion: A high level of antibiotic resistance was observed in our study and maximum isolation rate of Acinetobacter was in the ICUs associated with respiratory tract infection. Acineobacter baumani was the most predominant species. Other species of Acinetobacter are also isolated and encountered in hospital acquried infection, though they are sensitive to presently used antimicrobials but in future have potential to acquire resistance. The analysis of susceptibility pattern will be useful in understanding the epidemiology of this organism in our hospital setup, which will help in treating individual cases and controlling the spread of resistant isolates to other individuals. Keywords: Acinetobacter Species; Antimicrobial Susceptibility Pattern.