Background: Acute non-traumatic abdominal pain is one of the most common presenting symptoms in emergency of a general surgery department. The aetiology is varied for a common symptom and so it is very important to come to an early diagnosis for proper management. Objective: To identify the spectrum of diseases leading to acute onset non-traumatic abdominal pain, presented in the general surgery department. Design: Institution based prospective observational study. Setting: Department of General Surgery, B.S. Medical College, Bankura. Duration: January 2015 to December 2015. Materials and methods: All patients more than 12 years of age presented with non-traumatic abdominal pain in the general surgery department from January 2015 to December 2015 were included in this study. The demographics, diagnosis and outcome were noted in a predesigned, pretested proforma and analyzed. Results: The study cohort included total 3538 patients out of which 54.35% were male. Majority (54.74%) of the patients were in 25-50 years of age group consisting of 26.59% male and 28.15% female. Patients who came for treatment were mostly from lower class of socio-economic group (59.97%) according to SEC by Government of India. 56.21% patients presented with pain for >72 hours duration. The most common site affected being lower abdomen (46.72%), followed by upper abdomen (36-43%) and periumbilical (12.37%). 4.46% patients presented with generalized abdominal pain. Pain was sudden in onset in 67.21% patients (2378/3538) and 54.97% patients were having 5-7 scale pain at presentation according to Numeric rating scale of pain. Most common cause was found to be acute appendicitis (16.3%) followed by acute pancreatitis (11.92%), acute cholecystitis (9.60%) and renal colic (7.49 %). 74.61% (2640/3538) patients were managed conservatively and surgical intervention was needed in 25.38% patients. In hospital mortality rate was 1.72%. Conclusion: The most common cause of non traumatic acute abdominal pain in this study was acute appendicitis affecting young and middle aged population, followed by acute pancreatitis and acute cholecystitis.