To clarify the clinical outcome of peripheral T-cell lymphomas (PTCLs), we conducted a retrospective review comparing the outcomes of patients with PTCL (nodal peripheral T-cell lymphoma, unspecified, n=34 ; angioimmunoblastic T-cell lymphoma, n=12) to those with diffuse large B-cell lymphoma (DLBCL, n=48). All patients received CHOP-based chemotherapy without rituximab. PTCL patients presented at a more advanced clinical stage (91% vs. 65%, P<0.002) with a poorer performance status (26% vs. 17%, P<0.002) than DLBCL patients. The complete response rate among PTCL patients was significantly lower than among DLBCL patients (39% vs. 67%, P<0.008), as was the 3-year overall survival rate (26% vs. 50%, P=0.005), and Cox multivariate analysis revealed immunophenotype, performance status, and extranodal site involved to be significantly associated with shorter overall survival (P=0.045, P=0.007, and P=0.034, respectively). Our findings suggest that PTCL patients tend to have a poor prognosis associated with several initial risk factors. Moreover, the T-cell phenotype itself appears to have a significant impact on overall survival. Thus, standard CHOP chemotherapy may be inadequate for PTCLs, especially in patients with high-risk factors. The development of newly stratified therapies for the treatment of PTCLs would be highly desirable.