The authors analysed ultrasonography (US) findings in patients with clinical signs of acute appendicits duringa 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 visualized by high-resolution, realtime US according to the graded-compresion method described y Puylaert. The following results noted: 1. Sonongraphically visualized 136 cases were the target-appearance appendix in 47 cases, the fluid-filled appendix in 66 cases andthe 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. Appendicits perforation was predictable in 21 cases of 24cases. 3. Acute appendicitis was 24 cases(59%) among 41 cases who were sonographically visualized with appendicealwall thickening less than 3mm and 77 case (81%) among 95 cases with wall thickening more than 3mm. 4. When theresults in women were analyzed seperately (n=176), the sensitivity was 86%, the speicifcity was 76% and the accuracy was 80%. In women, US was helpful for the differential diagnosis between acute appendicitis and other gynecologic disease. 5. In men(n=69), the sensitivity was 88%, the specificity was 75% and accuracy was 80%(n=245). Graded-compression US is the examination of choice in the patients with clinical signs of acute appendicits, particularly in women.