The terminology of acute abdomen refers to a sudden and severe abdominal pain of unclear etiology that is less than 24 hours in duration. It is the presentation of an undiagnosed previous abdominal pain prior to a clinical presentation in primary or secondary care. Objectives: To determine the factors causing acute abdominal pain in the patients presented in the A&E department of mayo Hospital, Lahore. Design: Cross sectional study design. Place:Lahore Study period:6 months. Subjects and methods:A cross sectional study was conducted. Total 100 subjects were recruited in the study. Selection was made on laid down criteria after taking due consent from subjects. Interviews were conducted through a pretested questionnaire. The data was collected and compiled and then analyzed through SPSS 22 and described in the demographic characteristics using frequency tables. Result: Out of 100 subjects ,acute abdomen was found to be more in people above 30 years of age(52%)[mean:52+ .502SD]. It was more common among the females(57%) as compared to the males(42%).It was also seen that acute abdomen was more in uneducated(71%)as compared to educated(29%) people.It is also more common in married people(68%)as compared to unmarried people(32%).It is also more common in people living in urban area(92%)than in people living in rural area(8%).it is more frequently seen in people having income less than 15000/month(85%)than in people having income more than 15000/month. It was also found that the pain is more frequently found in right iliac fossa(18%) epigastric (36%) and umbilical(19%) region. Keywords: Acute abdomen,renal colic,gastric ulcers.