The introduction of rituximab (R) has measurably improved the outcome of patients with follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL). To evaluate the outcome of patients with FL and DLBCL under R plus CHOP therapy, we performed a retrospective analysis in Yokohama City University Hematology Group in Japan. Five hundred and twenty-six patients (158, FL ; 368, DLBCL) were scheduled to undergo primary therapy with 6 cycles of full-dose R-CHOP therapy with curative intent. The median observation periods in living patients with FL and DLBCL were 45 months and 43 months, respectively. The complete response, 5-year progression-free survival (PFS), and 5-year overall survival (OS) rates were 86%, 50%, and 92% in the FL group, and 89%, 72%, and 80% in the DLBCL group, respectively. Although PFS was significantly better in the DLBCL group than in the FL group, OS was significantly better in FL patients. We also found that the OS and PFS of grade 3 FL patients were not statistically different from those with grade 1-2. These findings indicate that all grades of FL should be categorized simply as "FL" with regard to R-CHOP therapy. Our results also demonstrate the incurability of FL (grade 1-3B), even with R-CHOP therapy.