Behcet's disease is a multi-systemic vasculitis and characterized by systemic organ involvement. Although the gastrointestinal and systemic features of Behcet's disease and inflammatory bowel disease overlap to a considerable extent, they are generally viewed as two distinct diseases. A 39-yr-old female was diagnosed as having Behcet's disease. She was admitted to our hospital because of oral and genital ulcer, lower abdominal pain, and frequent diarrhea. Colonoscopy showed diffuse involvement of multiple longitudinal ulcers with inflammatory pseudopolyps with a cobblestone appearance and ano-rectal fistula was suspected. These findings are extremely rare in Behcet's disease. However, there were no granulomas, the hallmark of Crohn's colitis. Microscopically, perivasculitis and multiple lymph follicles compatible with Behcet's disease were seen. Although being rarely encountered, multiple longitudinal ulcers, cobblestone appearance, and ano-rectal fistula can develop in Behcet's disease, as in Crohn's colitis. Therefore, Behcet's disease and Crohn's disease may be closely related and part of a spectrum of disease.