Background: Acute appendicitis is a frequently encountered surgical disease. Detection is difficult even with imaging and blood investigations. Total leukocyte count is a promising investigation. Its role in the confirmation of acute appendicitis is investigated and analysed in the present study. Aim and Objective: To determine the accuracy of leukocyte count in diagnosing acute appendicitis. Methods: Patients having suspicion of acute appendicitis treated by surgical intervention (appendicectomy) were included in the study. The leukocyte count measured before surgery, was compared with histopathology findings of the appendix. Parameters of diagnostic accuracy of leukocytosis were measured by standard formulae. Results: There were total 180 suspected cases of acute appendicitis which underwent surgery. Among the cases, 132 were having raised total leukocyte count (TLC) and 48 with normal leukocyte count. The histopathology revealed inflamed appendix in 121 (true positive) out of 132 patients of raised TLC group while 41 (false negative) out of 48 patients of normal TLC group. The sensitivity of the test was calculated to be 74.69%, while the specificity was 38.89%. The positive predictive value (PPV) was found to be 91.67%, indicating that among the cases with high TLC and inflamed appendix, 91.67% of them actually had acute appendicitis. However, the negative predictive value (NPV) was only 14.58%, indicating that among cases with normal TLC and normal appendix, only 14.58% of them actually had no acute appendicitis. Conclusions: Leukocyte count is a great criteria for ruling in acute appendicitis, but a poor criteria to rule out acute appendicitis because of its low negative predictive value and specificity. Clinical diagnosis still holds more importance over biochemical and radiological diagnosis.