Objectives: Acinetobacter species are one of the most frequent nosocomial pathogen and can cause a wide range of infections, including bacteremia, pneumonia, urinary tract infection, peritonitis, etc. This organism is becoming resistant to a large group of antibiotics, especially β-lactam antibiotics and also carbapenems. Aim: To determine the prevalence of Acinetobacter species in the patients of NICU and PICU of a tertiary care paediatric hospital and also to study their resistance pattern. Materials and Methods: This is a retrospective study done over a period of 12 months from January 2016 to December 2016. The Acinetobacter species isolates by all the clinical samples from NICU and PICU were identified by colony characteristics and biochemical reactions. The resistance patterns of these isolates were identified using various antibiotics by Kirby-Bauer disc diffusion test as per CLSI guidelines .Their antibiogram data and a clinical correlation was made to assess their pathogenic status and mode of acquisition. Results: Acinetobacter species was isolated in 280(30.7%) samples out of 911(17.75%) culture positive isolates from a total of 5131cultures from NICU and PICU. Maximum isolates were from Tracheal aspirate 93 (57%) followed by pus (52.71%) and blood 88(19.4%). The organism showed high rate of resistance to cefazolin (96.5%) ampicillin (91.8%), amoxyclav (85.2%) ceftriaxone (88.5%), piperacillin (82.9%), ceftazidime (77.5%), amikacin (75.2%) and ciprofloxacin (86.9%). The organism showed moderate resistance to Imipenem(68%) , meropenum (65%) and colistin (60%). Conclusion: In this study, Acinetobacter species was resistant to many drugs including imepenum and meropenum and there was a significant relationship between patients on mechanical ventilation, length of hospital stay and drug resistance.