A 59-year-old man presented in January 2003 with generalized lymphadenopathy. An inguinal lymph node biopsy showed mantle cell lymphoma (MCL). After four courses of Rituximab-CHOP therapy were administered, complete response (CR) was achieved. However, in August 2003, he presented with neck lymphadenopathy and was found to have relapsed. Several salvage therapies (ESHAP, Hyper-CVAD/MTX-ara-C) were administered, but CR was not achieved. After two courses of single-agent chemotherapy with CPT-11 (40 mg/m2) were administered on days 1, 2, 3, 8, 9, and 10, CR was achieved. Several studies reveal that the long-term prognosis for MCL with conventional therapy is poor. This report describes CPT-11 therapy for MCL and provides evidence that CPT-11 is another therapeutic option in refractory cases of MCL.