Introduction: Peripheral T-cell lymphomas (PTCL) are heterogeneous and aggressive malignancies recognized by the 2016 WHO classification. The goal of this study is to evaluate the prognostic role of pretreatment serum albumin level (PAL) in aggressive PTCL subtypeS in a cohort of patients from Peru, Argentina, Chile, and Colombia. Methods: Patients with PTCL treated between January 1991 and December 2017 were analyzed. Diagnosis of PTCL was based on histological findings. Overall survival (OS) curves were estimated using the Kaplan-Meier method and compared using the log-rank test. Uni and multivariate logistic and Cox regression analyses were performed. Results: 425 patients with PTCL met inclusion criteria; 48% were peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS),38% were adult T-cell leukemia/lymphoma (ATLL) and 18% where others (ie. anaplastic, angioimmunoblastic, NK/T cell, enteropathy-associated and hepatosplenic lymphoma). The median follow-up was 3.5 years. 54% were younger than 60 years, and 55% were men. An ECOG ≥1 was seen in 48%, B symptoms in 65%, clinical stage III-IV in 75%, and high LDH level in 55% of the patients. PAL was <3.5 g/dl in 56% of the patients. 52% were classified as high/high-intermediate IPI score (31% and 21%, respectively), and 61% as high/high-intermediate PIT score (28% and 33%, respectively).75% of patients received systemic therapy (25% best supportive care). The IPI score and PIT score were useful to discriminate the highest risk group. High/high-intermediate had worse survival than low/low-intermediate IPI score (HR 2.92, 95%CI, 2.13-4.01, p<0.001); and high/high-intermediate had worse survival than low-low intermediate PIT score (HR 2.63, 95% CI, 1.88-3.68, p<0.001). In the multivariate analysis, the ATLL group had worse survival than PTCL-NOS (HR 1.82, 95% CI, 1.32-2.50, p<0.001). PAL<3.5 had poor survival than PAL>3.5 (HR 1.82, 95% CI, 1.33-2.48, p<0.001). The median OS at 5 years was 1.5 years with Albumin >3.5 and 0.6 years with Albumin <3.5. When combining PAL<3.5 g/dl and IPI score (IPI-alb), patients were stratified in 3 risk categories: IPI-alb 0 with a median OS of 3.5 years, IPI-alb 1 with 1 year and IPI-alb 2 with 0.4 years. The IPI-alb 1 had worse survival than IPI-alb 0 (HR 2.13,95% CI 1.38-3.28, p=0.001), and IPI-alb 2 had worse survival than IPI-alb 0 (HR 3.73, 95% CI, 2.43-5.71, p<0.001). When we combine PAL<3.5 g/dl and PIT score (PIT-alb), were also stratified in 3 risk categories: PIT-alb 0 with a median OS of 3.5 years, PIT-alb 1 with 1 year and PIT-alb 2 with 0.4 years. The PIT-alb 1 had worse survival than PIT-alb 0 (HR 2.08, 95% CI 1.30-3.33, p=0.002), and PIT-alb 2 had worse survival than PIT-alb 0 (HR 3.38, 95% CI, 2.13-5.38, p<0.001). Keywords: prognostic indices; T-cell lymphoma (TCL).