We report a rare case of multiple lymphomatous polyposis of the gastrointestinal tract, with emphasis on the radiological, colonoscopic, and morphological findings. The underlying condition proved to be a poorly differentiated lymphocytic lymphoma. This is the first case of multiple lymphomatous polyposis in which immunologic marker studies are described and B cell origin confirmed. The different types of lymphoid polyps of the colon and the role of immunohistology are also discussed.