Purpose : The purpose of this study is to determine the detection rate of early gastric cancer and to measurethe focal gastric wall thickening incomputed tomography. Materials and Methods : From November 1991 to November1993, 19 patients (age ; 33 - 76 years, male ; female = 14 ; 5) with surgically proven early gastric cancer wereexamined by upper gastrointestinal series and abdominal computed tomography. Twenty lesions in these patients wereincluded in this study. Computed tomography was performed with conventional technique using gastrografinR (17cases) or water filling (2 cases) method in supine position. Additional scans were obtained either in right downdecubitus (15 cases) or supine position (4 cases) with an ingestion of gas forming agent. We determined thedetection rate of early gastric cancer at computed tomography and measured the maximum thickness of the lesion.Results : The pathologic types of the early gastric cancer were type IIb + II c in 5 cases, type IIc in 6, typeIII in 3 and type I, I + IIc, IIa, IIb, IIb + III and IIc + III in one, respectively. Seventy-five percent (15cases) of early gastric cancer was detected at upper gastrointestinal series and fifty percent (10 cases) atcomputed tomography. Computed tomography could detect 100 % of elevated carcinomas (3/3) and 41 % of depressedcarcinomas (7/17). The maximum thickness of the lesion ranged from 7 mm to 11 mm (mean ; 8 mm). Conclusion ; In awell-distended stomach, CT could detect focal gastric wall thickening (mostly, less than 1 cm) caused by earlygastric cancer in half of the cases.