Sixty eight surgically proven appendicitis patients with 41 cases of nonperforated appendicitis and 27 cases of perforated appendicitis were evaluated based on the computed tomography (CT) appearances of phlegmon, abscess, extraluminal air, defect in enhancing appendiceal wall, appendiceal wall enhancement, lateroconal fascial thickening, bowel wall thickening, appendicolith, periappendiceal fluid and omental haziness. The sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and accuracy for each finding is calculated by comparing the predicted outcome to the surgical and pathologic outcome. We concluded that direct and indirect CT appearances can differentiate perforated from nonperforated appendicitis. A dedicated search for indirect signs may be helpful in difficult case.