Aim: To study the frequency and factors associated with peritoneal involvement among patients operated for acute appendicitis in a tertiary care hospital.

Place and duration of study: Department of Surgery, Benazir Bhutto Hospital Rawalpindi Pakistan from 1^stJuly 2020 to 30^thJune 2021.

Methodology: This comparative cross-sectional study 500 patients diagnosed as acute appendicitis and operated by consultant surgeon were included. Peritoneal involvement was defined as signs of inflammation or infection on abdominal lining observed by operating surgeon during the time of surgery. Factors like age, gender, presence of comorbid illnesses and history of previous abdominal surgeries were associated with presence of peritoneal involvement.

Results: There were 305 (61%) males while 195 (39%) were females with mean age was 32.331±4.544 years.Four hundred and forty two (88.4%) did not show any peritoneal involvement at the time of surgery while 58 (11.6%) had peritoneal involvement.  Chi-square test revealed that history of previous abdominal surgeries and advancing age had statistically significant association with peritoneal involvement among the study participants (p-value<0.05).

Conclusion: Peritoneal involvement was found in considerable number of patients operated as acute appendicitis by the treating surgeons. Patients with previous history of abdominal surgeries and advancing age were more at risk of having peritoneal involvement in our study.

Keywords: Acuteappendicitis, Peritonitis, Risk factors, Frequency