Follicular lymphoid hyperplasia is commonly seen when performing pediatric endoscopy. But in adults, these findings can imply an underlying gastrointestinal or systemic illness, besides the normal variant. On the other hand, colonic involvement of chronic lymphocytic leukemia (CLL) is seen in about 5% to 20% of autopsy cases. However, there have been few reports on the colonoscopic appearance that corresponds to colonic involvement by CLL, and the reported colonoscopic appearances have included polyps, ulcers, granularity, submucosal nodules, erythema, the red ring sign etc. We report here on a case of CLL neoplastic lymphocyte involvement of the terminal ileum and colon as a form of lymphoid hyperplasia, and this was seen when performing colonoscopy. (Korean J Gastrointest Endosc 2009;39:244-247)