Background and objectives: Since the advent of antibiotics in the 1930’s and 1940’s antibiotic resistance has been an issue. In the last decade, antibiotic resistance has become a major issue. Every orthopedic surgeon faces on a daily basis an increasing problem of antibiotic resistance in the effort to treat and prevent infections .In view of these above mentioned problems it becomes necessary to identify as early as possible all infections that occur ,determine their sensitivity and institution of appropriate antibiotics. The objectives of this study was to identify the common micro organisms that infect open tibial fractures in our hospital and determine the culture sensitivity patterns during the course of treatment in this hospital; To evaluate whether pre debridement and post debridement cultures are predictors of infection in open fracture wounds. Methods: A prospective study was conducted in the Orthopaedics department of Tirtiary care Hospital, Surat where 27 cases of open tibial fractures were analysed to determine the infective organism and the culture sensitivity pattern of the isolated organism. A study was also conducted on wound bacterial cultures and their effectiveness in determining the prognostic value in deep wound infections. Study design: All patients underwent clinical examination and history noted. Demographic details date and time of injury, mechanism of injury and time elapsed since injury to presentation in emergency department was noted. Wounds were swabbed before and after debridement and fractures were classified based on Gustilo Anderson’s Grading system. Appropriate treatment for bony as well as soft tissue injury was carried out and patient was followed up in the ward to note the infections that developed from pre as well as post debridement cultures. Results: Of the 27 pre and post debridement samples that were sent it was found that 41% of pre debridement samples were positive for infective organisms and of these 59% grew the infective organism in culture. In the post debridement series, only 20 % of the cultures grew the infective organism, of which only 64% cases got infected. Hence pre debridement cultures were more accurate in predicting open fractures infections. However of the cases that did become infected the infective organism was isolated in 85% cases. The most common organism that was isolated was found to be non fermenting gram negative bacillus followed by Pseudomonas in our study and the antibiotics recommended for treating these infections was found to be Cefeperazone sulbactum combination followed by Amikacin. Conclusion: In summary, the use of pre and post debridement bacterial cultures has got a value in determining infections in open tibial fractures. The kind of organism will differ from hospital to hospital and culture sensitivity pattern will also vary. The most common organism that was encountered in my hospital was non fermenting gram negative bacillus followed by Pseudomonas; and the antibiotic of choice was found to be cefeperazone sulbactum combination followed by Amikacin