Aim: The aim of this study to determine the value of pre operative hyperbilirubinemia as a predictor of complicated appendicitis. Material and methods: The study was a prospective observational study conducted in the Department of General Surgery, Vardhman Mahavir Medical College and safdarjung Hospital, New Delhi, India for 15 months. Total 120 patients who were diagnosed to have appendicitis and admitted in surgery department and who underwent appendicectomy were included in the study. Clinical examination, blood routine examination, Alvarado score, ultrasound abdomen, histopathology examination, pre and post- operative values of total bilirubin, direct bilirubin and indirect bilirubin were studied. Results: In our study 70 (58.33%) were males and 50 (41.67%) were females. Out of the 120 cases 52 were complicated. 74 cases had elevated bilirubin preoperatively in which 41cases were having complications like gangrene, suppuration and perforation. Out of the 74 cases that had elevated bilirubin pre operatively 38 (51.35%), the bilirubin level came down to normal limits after 72 hours of appendicectomy. On histopathology, 68 were acute appendicitis, 17 were perforated appendicitis, 12 were gangrenous appendicitis, 23 were suppurative appendicitis. From the study of sensitivity and specificity of pre-operative total bilirubin values in predicting perforated appendicitis, it was found that preoperative total bilirubin value of 1.59 mg/dl had the best sensitivity and specificity. Taking preoperative total bilirubin value 1.59 mg/dl as cut off in predicting perforated appendicitis the sensitivity was 68.8, specificity was 95.1 with an accuracy of90.2. Conclusion: Patients with appendicitis with elevated bilirubin levels have more chance for complications like perforation, gangrene and suppuration.