Background: Acute appendicitis is a common surgical emergency. Diagnosis may be difficult with little help from radiological and laboratory investigations. Total leukocyte count is one of the helpful investigations, being evaluated in this study. Methods: The patients presenting with right lower quadrant abdominal pain whom were diagnosed as having acute appendicitis and later underwent appendicectomy were included in the study. The preoperative leukocyte count was compared with histo-pathology findings of removed appendix. Sensitivity and specificity of TLC was calculated by standard formulas. Results: The sensitivity and specificity of TLC as calculated in this study is 76.5% and 73.7% respectively while positive predictive value is 92.5%. Conclusion: TLC although not a diagnostic criteria for acute appendicitis but still is helpful investigation in decision making.