OBJECTIVES:  The study was undertaken with the objective to understand the pattern of antimicrobial drug usage in the ICU settings of an Indian private tertiary care hospital. METHODS:  The study was designed in a prospective manner in two phases, observational and interventional, over a period of ten months in a private tertiary care hospital. The data of patients was collected from the different ICUs in the hospital and all the information related to the AMD use was noted along with the sensitivity patterns. RESULTS:  A total of 665 patient data was captured. The average number of medications prescribed was 12.6 and 13 in interventional and observational phase whereas the average number of AMD prescribed was 2.4 and 2.7 respectively. Over 92% of the AMDs were prescribed by parenteral route and about 50% were prescribed from NLEM and approximately 20% by generic name. Most frequently utilized classes of drugs were third generation cephalosporins, aminoglycosides and flouroquinolones. Documentation of surgical prophylaxis was observed in 81% of the cases in the surgical specilities in both the phases. 64% of the patients in the observational phase and 55% in interventional phase received surgical prophylaxis at appropriate timing. In less than one half of the patients, AMDs were prescribed on the basis of leucocytosis, fever, and positive chest X ray or compelling medical condition. CONCLUSIONS:  The present study has provided useful findings on the antimicrobial drug utilization patterns in the ICU and recommended that safer use of AMDs need to be promoted along with justified therapeutic regimen.