We report a case with low-grade MALT lymphoma of the rectum in a 32-year-old man. Primary lymphoma of thecolon is rare and comprises less than 1 % of large bowel malignancies. Recently, large part of colonic lymphomahave been shown to be MALT lymphoma, which is a distinct type of B-cell lymphoma. The radiologic findings of thiscase are mucosal nodularity with shallow ulcers in the rectum, as seen on bar-ium enema, and rectal wallthickening, as seen on CT. There was no evidence of intra-abdominal lym-phadenopathy nor hepatosplenomegaly. Suchradiologic findings are rather similar to the findings in cases of inflammatory bowel disease, rending thedifferential diagnosis difficult.