HIV infection has been associated with an increased risk of developing several types of malignancies, including aggressive peripheral T-cell lymphomas (PTCL). However, this is a rare occurrence with no more than a hundred cases reported in the literature. The purpose of this multicenter study is to describe the characteristics and to identify prognostic factors in patients with HIV-associated PTCL. Data from HIV-positive patients with a pathological diagnosis of non-primary cutaneous, non-leukemic PTCL were gathered retrospectively and are reported using descriptive statistics. Univariate and multivariate survival analyses were also performed. Fifty one patients were included in our analysis. Median age was 38 years with a 5:1 male-to-female ratio. Patients presented with a median CD4+ count of 173 cells mm-3, and a median HIV viral load of 334,787 copies ml-1. The median time from HIV diagnosis to PTCL diagnosis was 4.5 years. About 75% of patients presented with advanced clinical stage and 66% with B symptoms. The most common subtypes were PTCLU (61%) and anaplastic large cell lymphoma (ALCL, 22%). None of the ALCL patients tested expressed ALK. The median overall survival (OS) for the group was 12 months. In the multivariate survival analysis, the use of HAART and patients' performance status were independently associated with OS. HIV-associated PTCL presents predominantly in young men with low CD4+ counts and high HIV viral loads. Both HIV-related and lymphoma-related factors were associated with OS. © 2011 Wiley-Liss, Inc.