BACKGROUND: Acute Appendicitis is the most frequent surgical emergency encounterd worldwide. This study was conducted for evaluation of modified alvarado scoring system in diagnosing Acute Appendicitis. OBJECTIVES: The aim of the study is to evaluate the efficacy of modified alvarado scoring system as a diagnostic tool ito aid early and accurate diagnosis of Acute Appendicitis. METHODS: This was a prospective study conducted in Government Dharmapuri Medical college Hospital from 2015 to 2016. It included 120 cases of suspected Acute Appendicitis  admitted in our hospital during that time. RESULTS: Modified Alvarado scoring system , sensitivity is 84.26%, specificity 10.83%, positive predictive value 84.26%. Negative appendicectomy rate was 2.87%. Missed Appendicitis rate 2.5%. CONCLUSION: Modified Alvarado scoring system had a diagnostic accuracy of 97%, seems to be ideal for supporting the diagnosis of Acute appendicitis, because it is non–invasive, doesn’t require specific equipments.