Background: Acute appendicitis is one of the most common acute intra-abdominal infections seen in surgical departments, which can be treated easily if an accurate diagnosis is made on time. Otherwise, delay in diagnosis and treatment can lead to perforation of the appendix &diffuse peritonitis. Materials and Methods: A prospective study was conducted on 112 patients who were operated for acute appendicitis in department of General surgery, Bowring & Lady Curzon Hospitals, BMCRI, to determine the role and predictive value of the total leucocyte count (TLC), C-reactive protein (CRP) and percentage of neutrophil count in the diagnosis of acute appendicitis. Preoperative TLC, CRP and percentage of neutrophil count were determined and were compared with the results of the histopathology of the removed appendix. Results: Of all the patients studied, 94 had histopathologically positive appendicitis. The TLC was found to be significantly high in 82 patients who proved to have acute appendicitis, whereas CRP was high in 88 patients and neutrophil percentage was raised in 87 patients; 6 patients had a normal CRP level. Thus, TLC had a sensitivity, specificity &positive predictive value of 87.23%, 44.44% and 89.13% respectively. CRP had a sensitivity, specificity & positive predictive value of 93.61%, 77.77% and 95.65% respectively. Percentage of neutrophil count had a sensitivity, specificity & positive predictive value of 92.55%, 38.88%, 88.77% respectively. When used in combination, there was a marked improvement in the sensitivity, specificity and the positive predictive value to98.76%, 86.66% and 97.56% respectively. Conclusion: The inflammatory markers, i.e., TLC, CRP and neutrophil count can be helpful in the diagnosis when measured together as this increases their sensitivity, specificity & positive predictive value significantly.