Diffuse large B-cell lymphoma (DLBCL), as defi ned by 2008 World Health Organization (WHO) classifi cation, is the most common subtype. Rituximab (R), a chimerical monoclonal antibody against the CD20 B-cell antigen, has shown improved outcomes in patients with newly diagnosed DLBCL. Based on clinical results, a retrospective analysis was performed of treatment outcome, using rituximab, in patients with DLBCL. Materials & Methods: Two hundred and twenty newly diagnosed patients with non-Hodgkin’s lymphoma (NHL), between June 2001 and December 2006, were evaluated for histological subtypes and clinical characteristics. Ninety-nine patients with DLBCL were investigated further for clinical results after CHOP-like chemotherapy with or without rituximab. Results: Among 220 patients with NHL, 172 (78.2%) patients had B-cell lineage and 35 (15.9%) T/NK-cell lineage. Ninety-nine patients were diagnosed with DLBCL, which was the most common B-cell lineage subtype and accounted for 45% of the patients with NHL. Among the 99 patients with DLBCL, 43 received R-CHOP like chemotherapy (R-CHOP group), 29 received CHOP-like chemotherapy alone (CHOP group), 13 had other chemotherapy regimens, and 14 received supportive care only. The response rate was signifi cantly higher in the R-CHOP group compared to the CHOP group (86% vs. 58.6%, p=0.012). The progression free survival was signifi cantly higher in the R-CHOP group (p=0.05, HR=0.524, CI, 95%, 0.255-1.075). The survival benefi t was also more favorable in the R-CHOP group (p=0.06, HR=0.520, CI, 95%, 0.253-1.067). Conclusions: DLBCL is the most common subtype of NHL. The addition of rituximab to CHOP-like chemotherapy increased the response rate and improved the therapeutic outcome with regard to the progression free survival. A longer follow-up duration is necessary to evaluate overall survival.