Plasmablastic lymphoma (PBL) is a distinct variant of diffuse large B-cell lymphoma initially described in HIV-positive patients. Several studies have reported the occurrence of PBL in HIV-negative patients, but comparative data are lacking. The goal of this study was to compare the characteristics of HIV-positive and HIV-negative patients with PBL. A MEDLINE search was undertaken through August 2009 for cases of PBL in HIV-positive and HIV-negative patients. Cases were identified and clinicopathological data were gathered. χ(2) was used to compare categorical and t-test to compare continuous variables between groups. Calculated Kaplan-Meier survival estimates were compared using the log-rank test. Cox proportional-hazard regression was used for multivariate analysis. From 228 identified cases of PBL, 157 were HIV-positive and 71 HIV-negative. HIV-positive patients were younger, and more likely to be men, present with oral involvement, respond to chemotherapy, and express CD20, CD56, and EBV-encoded RNA than HIV-negative patients. In univariate analysis, age ≥60, advanced stage, bone marrow involvement, no chemotherapy, Ki-67 expression >80%, and HIV-negative status were associated with worse overall survival. In multivariate analysis, advanced stage and no chemotherapy were independent adverse prognostic factors. In conclusion, HIV-positive and HIV-negative patients with PBL have different clinicopathological characteristics, including a better response to chemotherapy and longer survival in HIV-positive patients.