The risk for the development of malignancy in Crohn's disease is not as well defined as it is with ulcerative colitis. The risk for the development of small bowel adenocarcinoma is greater in patients with Crohn's disease than in the general population although the magnitude of this increased risk is unclear. Risk factors associated with the development of small bowel carcinoma in Crohn's disease include male sex, duration of disease, associated fistulous disease, and the presence of surgically excluded loops of bowel. Crohn's colitis has been associated with an increased risk of colorectal carcinoma in patients with long-standing colitis, strictures, fistulae, and right-sided colonic disease. Secondary gastrointestinal carcinomas are rare in Crohn's disease. This article reviews the current literature regarding the association of various malignancies in Crohn's disease. Although concentrating on population based and case-control studies, it includes referral center studies as well as case reports.