We report a successfully treated case accompanied by portal venous gas, which was associated with splenic abscess due to penetration of colon cancer. In June, 1998, a 67-year-old Japanese man was referred to our hospital because of a continuous fever over 40 degrees C and portal venous gas detected by computed tomography (CT). CT revealed low density areas in the spleen and wall thickening of the descending colon next to the spleen. Barium-enema examination demonstrated an extrinsic filling defect in the splenic flexure of the colon. Splenectomy, resection of the pancreatic tail and left hemicolectomy were performed Histopathological studies showed moderately differentiated adenocarcinoma, which made a fistula at the bottom of the ulceration to the spleen. The postoperative course was uneventful. The portal venous gas was likely to have resulted from a bacterial infection in the portal venous systems secondary to the splenic abscess.