BACKGROUND/AIMS: The aim of this study was to assess the clinical features and therapeutic responses of perianal lesions in Crohn's disease. METHODS: We retrospectively reviewed medical records of 94 cases with perianal lesions among 231 cases registered as Crohn's disease in Seoul National University Hospital between January 1975 and June 2001. The cases were investigated after dividing into two different groups. One group included the cases registered between January 1975 and December 1996 and the other group between January 1997 and June 2001. RESULTS: The perianal lesions were observed in 41% of the cases. Perianal lesions were more frequent in colonic Crohn's disease after 1997, but not before 1996. Fistula was significantly prevalent, followed by abscess, fissure, and stricture. Perianal lesions preceded intestinal symptoms such as abdominal pain and diarrhea in 25% of the cases. The remission rate with non-specific conservative treatment (10%) was lower than that before 1996. The remission rate after specific treatment (77%) was higher than that after surgery (53%). In cases of specific treatment, cumulative relapse rates were 7% in 1 year and 39% in 5 years. CONCLUSIONS: Crohn's disease should be considered in young male patients who have the refractory perianal lesions. Perianal lesions should be managed initially with medical treatment.