OBJECTIVES: Our aim was to retrospectively investigate the data from our institute the response rate and outcome in patients with primary mediastinal B-cell lymphoma (PMBL) who received the rituximab in combination with CHOP (RCHOP) followed by autologous stem cell transplantation (ASCT) or RCHOP followed by involved field radiation therapy (IFRT). METHODS: Sixty five patients with PMBL received RCHOP as first-line chemotherapy between January 2005 and December 2010. Forty of the 65 patients completed the planned subsequent IFRT after initial chemotherapy. Thirteen of the 65 patients received the front-line ASCT after RCHOP. Twelve patients received RCHOP alone. RESULTS: Thirty two of the 40 patients who received the RCHOP followed by IFRT have complete remission (CR) or CRu (CR/unconfirmed). All patients have CR or CRu after the ASCT. The progression free survival (PFS) and the estimated overall survival (OS) rate at 5 years for 32 CR/CRu patients in the RCHOP followed by IFRT group were 57 and 65%, respectively, as compared to RCHOP/ASCT group who were 94 and 100%, respectively. Twelve patients who received RCHOP alone had the same PFS and OS rate as the 40 patients who received RCHOP/IFRT (5-year PFS:62 vs. 65%, p = 0.068; 5-year OS:57 vs. 67%, p = 0.058). For all 65 patients, the age-adjusted international prognostic index (aaIPI) score remained the only predictor of a worse outcome. CONCLUSION: The PFS and OS rate of RCHOP/IFRT were found to be unsatisfied. RCHOP/ASCT showed a satisfactory PFS and OS rate.