Background/Aims: Both Crohn's disease and intestinal Behcet's disease cause transmural inflammation and require frequent surgical treatment. Long-term course of Crohn's disease has been well- known, but that of intestinal Behcet's disease have not been reported. We have evaluated operation and reoperation rates in intestinal Behcet's disease, and compared them with those of Crohn's disease. Methods: We retrospectively analyzed the medical records of 67 patients with intestinal Behcet's disease and 140 patients with Crohn's disease diagnosed from 1984 to 1997. Perforating indication for surgery is defined to include fistula formation, abscess, or free perforation. Their cumulative rates were calculated by Kaplan-Meier method and compared by log-rank test. Results: Cumulative operation rates in intestinal Behcet's disease were significantly higher than those in Crohn's disease and cumulative reoperation rates were also high in intestinal Behcet's disease. The patients with perforating type of intestinal Behcet's disease tended to receive reoperation earlier than the patients with non-perforating type (p=0.058). Moreover, perforating indication in Crohn's disease was a predictor for early reoperation (p=0.04). Perforating type of surgical indication was more frequent in intestinal Behcet's disease than in Crohn's disease (52% vs. 31%, p=0.048). Conclusions: Prognosis of intestinal Behcet's disease is worse than that of Crohn's disease, which is probably due to high perforation rate in intestinal Behcet's disease. (Kor J Gastroenterol 2000;36:504 - 514)