Esophagogastroduodenoscopy revealed small duodenal lesions in a 56-year-old Japanese man and a 92-year-old Japanese woman with stage IV follicular lymphoma. Magnifying endoscopy examination revealed tiny white deposits in the second duodenal portion of the former patient and slightly enlarged duodenal villi in the latter. In both cases, biopsy revealed infiltration of follicular lymphoma cells and incipient formation of neoplastic follicles. Here, we discuss the usefulness of magnifying endoscopy and narrow-band imaging for the detection of small duodenal lesions in follicular lymphoma cases.