Colon cancer is the most serious intestinal complication in patients with Crohn's disease. Although an association between Crohn's disease and colon cancer has not been clearly defined, a number of studies in western countries reported an increased rate of colon cancer in patients with Crohn's disease. In Korea, Crohn's disease is rare when compared to western countries, and only a single case of colon cancer associated with Crohn's disease has been reported. We recently experienced a 66-year-old women with colon cancer associated with Crohn's disease.