Background: Peritonitis is due to inflammationof the peritoneum. It is divided into primary and secondary peritonitis, and tertiary peritonitis is called when secondary peritonitis persists for more than 48 hours after an attempt at surgical source control. Secondary peritonitis accounts for 2% of emergency admissions and is the second leading cause of sepsis in patients in intensive care units worldwide. Peritonitis is one of the common surgical emergencies. Peritonitis is a significant cause of morbidity and mortality in surgical settings. The most common cause of acute peritonitis is duodenal perforation. Aim of the Study: To know the Etiology, clinical features of peritonitis in a teaching hospital. Materials and Methods: This study has been conducted in Gouri Devi Institute of Medical Sciences & Hospital, Durgapur, West Bengal (India) for 6 months in the department of General Surgery. We have included 46 total number of patients. Results: We have included total number of 46 patients in this study, out of these patients 24 are Males, 13 are Female patients and 9 are children. The common age group involved is between 20 years and 70 years in adults and in children 6 to 14 years. 8 patients died during the hospital stay.