The patient was a 68-year-old woman. She had an emergency admission to our hospital with chief complaints of sudden right abdominal pain and vomiting. A surgical scar was observed on the lower right abdomen and midline of the lower abdomen. There were high degrees of spontaneous pain and tenderness, and plain abdominal X-ray showed extensive dilatation and gas in the small intestine. An abdominal CT scan also showed marked dilatation of the small intestine lateral to the ascending colon, and the ascending colon was displaced toward the median. It was difficult to alleviate the pain with analgesics or sedatives. Thinking that it was either postoperative adhesive ileus or incarcerated internal hernia, we performed exploratory laparotomy. The laparotomy findings revealed no intraperitoneal adhesion, but the small intestine was impacted in the paracolic gutter of the ascending colon paracolic gutter. The hernia orifice was opened and the small intestine was reduced. The small intestine was not resected since the impacted small intestine was not necrotic. The hernia orifice was closed with sutures to finish the operation. The postoperative course was uneventful and she was discharged in remission after 18 days. An internal hernia occurring in the paracolic gutter of the ascending colon is a very rare disorder, and since the imaging findings were also distinctive, we report them together with some bibliographic consideration.