The purpose of this retrospective study was to investigate clinical features and treatment outcomes in patients with peripheral T cell lymphoma-unspecified (PTCL-U). Eighty-four patients who were diagnosed with PTCL-U between February 1995 and December 2005 were included in the study. Around 70% of the patients presented with stage III-IV disease; 24% were categorized as high or high-intermediate risk according to the International Prognostic Index (IPI) scoring system, and 45% were classified as groups 3 or 4 using the Prognostic Index for PTCL-U (PIT). Extranodal involvement was found in 51 of 85 patients (60%). Most of the initial chemotherapy regimens were anthracycline-based (75%). The overall response rates for patients treated with initial chemotherapy and salvage chemotherapy were 63.1% (52.6% of complete response (CR), 10.5% of partial response (PR)) and 35% (9% of CR, 26%of PR), respectively. The median progression-free survival and overall survival of all patients were 17.1 months (95% CI, 0.0-40.5) and 35.5 months (95% CI, 1.2-69.8), respectively. Poor performance status, the presence of B symptoms, IPI scores >or=3 and PIT class >or=2 were predictive prognostic factors for survival.