Primary goal in management of open fractures is prevention of infection of bone and soft tissue by early debridement, irrigation of wound and administration of broadspectrum antibiotics with stabilization of fractures. The pattern of organisms found in open fractures is important in the selection of antibiotics for prophylaxis and empirical treatment. In this prospective study, 50 consecutive patients of all ages, both the sexes, with open fracture of grade IIIB as per Gustilo- Anderson classification were evaluated for bacterial isolates. Higher rate of infection was found in patients with farm injuries and leg was most common site. The most common gram negative and gram positive bacteria isolated were E.coli and S.aureus respectively (19.5% each). On analysis of the predebridement, post-debridement, and third culture, positive pre-debridement culture showed maximum growth of Gram-positive bacteria. However, majority of these patients were found to have growth of different organism in their post-debridement culture reports.