Aims and Objectives :– 1. To detect commonest organisms in peritonitis due to duodenal ulcer perforation and to find out antibiotic sensitivity pattern to form antibiotic policy for peritonitis due to duodenal ulcer perforation. 2. To see response of patients after starting antibiotics according to the culture and sensitivity report. Materials and Methods:– Patients admitted with Duodenal Ulcer Perforation in SMIMER– Surat Hospital in Department of Surgery from May August 2017 to July 2019 were included in this study. 200 patients were studied during this period. Inclusion criteria: All patients with Duodenal Ulcer Perforation. Exclusion criteria: 1) Patients admitted with deranged vital parameters and not operated. 2) Peritonitis due to other Hollow Viscus Perforation. Discussion :– First 140 patients were given antibiotics imperically and next 60 patients were given antibiotics according to the culture and sensitivity report. Accordingly, most commonest organism, antibiotic sensitivity pattern, response of the patients after giving antibiotics according to culture and sensitivity with respect to post operative complications and hospitalization were noted. Conclusion:– 1 ) E.coli was the most commonest organism isolated from peritonitis due to duodenal ulcer perforation. 2 ) Maximum cultures were found sensitive to Piperacillin+Tazobactum and Cefotaxim. 3 ) Hospitalization and morbidity of patients were significantly reduced in patients treated with antibiotics according to culture and sensitivity.