and importance: Acute appendicitis is one of the most common causes of acute abdomen in surgical patients. The objectives of the study were to evaluate efficacy of Alvarado scoring system in preoperative diagnosis of acute appendicitis and correlating it with postoperative findings.The present study was a prospective study of 208 patients presenting with symptoms and signs of acute appendicitis to the emergency department during a period of 10 months. Patients who met the inclusion criteria were evaluated using Alvarado scoring system. The efficacy of Alvarado scoring system was assessed by calculating sensitivity, specificity, positive predictive value, negative predictive value and negative appendectomy rate.Total 208 patients were included in the study, which included 142 males and 66 females, at score of 7 or more, appendicitis was confirmed in 187/190 patients, while at scores7 appendicitis was confirmed in 10/18 patients. The sensitivity was 94.9%, the specificity was 72.7%, the positive predictive value was 98.4% and the negative predictive value was 44.4%. In the present study, negative appendectomy rate was 4.8.Clinical experience remains of major importance in diagnosing acute appendicitis. The Alvarado score is a simple, easy scoring system at both end of scale.