Ulcerative colitis (UC) is an inflammatory disease of the colon and rectum. Although colonic adenocarcinoma is a recognized complication of UC there have been few reported cases of gastrointestinal lymphoma arising in this setting. We describe our experience with such a case and review the literature that attempts to explain possible genetic etiologies for the malignant transformation of gastrointestinal lymphoid tissue to lymphoma as well as a link between UC and lymphoma.