The authors analysed ultrasonography findings in patients with clinical signs of acute appendicitis during a recent 7-months period. The comparative analysis between US findings and surgical-pathologic findings was performed in 193 cases who underwent surgery. There were 52 cases with a sonographically non-visible appendix whose symptoms spontaneously resolved. The inflamed appendix was visualied by high-resolutin, realtime US according to the graded-compression method described by Puylaert. RESULTS : 1. Sonographically visualized 136 cases were the target-appearance appendix in 47 cases, the fluid-filled appendix in 66 cases and the irregular marginated mixed echogenic mass-like density with surrounding fluid collection in 23 cases. The appendix was not visualized by US in 109 cases. 2. Appendicitis perforation was predictable in 21 cases of 24 cases. 3. Acute appendicitis was 24 cases among 41 cases who were sonographically visualized with appendiceal wall thickening less th n 3mm and 77 cases among 95 cases with wall thickening more than 3mm. 4. When the results in women were analyzed seperately, the sensitivity was 86%, the specificity was 76% and the accuracy was 80%. 5. In men, the sensivity was 88%, the specificity was 67% and the accuracy was 81%. 8. The overall sensitivity was 87%, the specificity was 75% and accuracy was 80%/ Graded-compresison US is the examination of choice in the patients with clinical signs of acute appendicitis, particularly in women.