Anisakiasis is a human disease caused by the accidental ingestion of larval nematodes, belonging to the family Anisakidae. The disease is caused by eating raw seafood dishes or undercooked fish and squid dishes. Considering the popularity of eating the raw fish in Korea, the incidence of anisakiasis has been increasing. The entire gastrointestinal tract from the esophagus to the rectum can be involved. Colonic anisakiasis is very rare, and it is relatively hard to diagnose compared with gastric anisakiasis. We are reporting a case of anisakiasis involving the ascending colon, which was treated by colonoscopic removal. (Intestinal Research 2004;2:120-123)