Gastric cancer is the most prevalent gastrointestinal tract malignancy in Korea. By the time the patient has symptoms, these tumors are usually advanced in stage. In high risk populations, screening such as double contrast UGI or gastric endoscopy is needed and patient with vague symptoms should be studied. However, these screenings have high diagnostic accuracy rate, only CT scan can identify accurately abnormal stomach wall thickening and intraabdominal tumor extension. And CT is important for planning of treatment, assessing surgical resectability, postoperative evaluation and prognostic implications. Author reviewed CT scan of 67 cases of confirmed gastric cancer by double contrast UGI or endoscopic biopsy, for 29 months from March 1983 to August 1985 at Department of Radiology, Pusan National University Hospital. The results were as follows : 1. The most frequent site of involvement of gastric cancer was gastric antrum in 49.9%(33/67). 2. by CT staging, stage 3 was 40.2 (27/67). 3. In CT scan analysis ,the structures involved by diect invasion were regional lymph nodes, pancreas, and gastrocolic ligament in order of frequency. The structures involved by distant metatases were liver, systemic lymph nodes, an dmesentery in order of frequency. 4. The diagnostic accuracy of CT staging was 73.9%(17/23) by correlation of surgical and phthological findings. 5. In determination of stage by CT, the rate inaccuracy of stage 2 was highest as 33%(2/6), and that of stage 3 was 29.2%(3/11). 6. Of all misdiagnoses, 83.3%(5/6) was owing to failure to differentiate lymph monde invasion from reactive hyperplasia of lymph node.