A 74-year-old-man was referred to our hospital to undergo examination and therapy for a rectal polypoid lesion. MALT lymphoma of the rectum (stage IE) was diagnosed by performing a biopsy of the tumor during colonoscopy. The patient received eradication therapy against Helicobacter pylori (H. pylori) because of chronic gastritis due to H. pylori, and a complete remission was documented after this therapy. However, MALT lymphoma recurred 18 months later. Our observations in this case suggest that eradication therapy against H. pylori may be useful not only for gastric MALT lymphoma but also for colorectal MALT lymphoma.