In 100 cases of histologically proven acute appendicitis and were studied prepoperative plain abdominal X-ray at department of Radiology of Ewha Womans University Hospital during the period from May, 1973 to May 1977, the preoperative plain abdominal radiographic findings and pathological findings were observed carefully and analyzed retropectively and compared each other. The following results were obtained: 1. The most frequent age was demonstrated in young adults as 73%. 2. Three most common radiographic findings are as follow: I) Alteration of Rt. psoas outline with scoliosis (70%) ii) Air fluid level in cecum or terminal ileum (66%) iii) Increased soft tissue density in RLQ (47%) 3. In perforated appendicitis, there was additional significance of extraluminal gas of radiographid findings as 52.4% and alteration of Rt. flank stripe as 47.6%. 4. In abscess formation, there was additional significance of alteration of Rt. flank stripe and deformity of the cecum and free flui of radiographic findings as each 60%. 5. In gangrenous appendicitis, deformity of the cecum of radiographic findings as 46.2% was disclosed significance more than increased soft tissue density in RLQ as 30.8%. 6. Positive radiographic findings was seen in 88% cases and all negative findings as 12% was shown in simple appendicitis only. 7. Complication was developed more in retrocecal appendicitis as 45.4% than in antececal appendicitis as 34% and more in male as 48.6% than in female as 33.3%.