Blunt colon injuries sometimes result in signs of peritoneal irritation requiring exploratory laparotomy. More frequently there are no specific symptoms, and this leads to a delay in diagnosis and management. Some imaging studies point to blunt colon injury, but gas in both the hepatic portal and mesenteric veins has rarely been reported. Hepatic portal venous gas (HPVG) is a rare roentgenographic picture, and its presence usually represents a serious intra-abdominal catastrophe. Computed tomography and plain abdominal X ray in a 52-year-old man with blunt abdominal injury showed significant gas in the portal venous system and pneumatosis intestinales of the ascending colon. Exploratory laparotomy revealed segmental necrosis of the transverse colon in front of the vertebrae. The presence of HPVG may have been due to mucosal disruption, vascular compromise or prolonged increased intra-abdominal pressure. Its presence in patients with blunt abdominal trauma suggests the possibility of bowel injury. Surgical exploration should be considered when HPVG is noted on roentgenographic studies.