Patients with inflammatory bowel disease (IBD) may be at increased risk of lymphoma. The majority of lymphomas in patients with IBD occur in areas of active inflammation. The relationship between IBD and lymphoproliferative disease is however unclear, since both chronic inflammation as well as medications used to treat IBD (especially immunosuppressives - Azathioprine or 6-MP - and anti-TNF alpha agents) have been associated with increased risk of lymphoma. We plan to study the association between IBD and lymphoma in a large, mixed, community based and referral population from the IBD database at Indiana University.