ABSTRACT: Primary testicular (PT) diffuse large B-cell lymphoma (DLBCL) is a rare and aggressive lymphoma with distinct clinical and molecular characteristics. To further improve the prognosis of PT-DLBCL, not only the common features of PT-DLBCL, but also the molecular heterogeneity within the PT-DLBCL entity, need to be better understood. In this study, 2083 microRNAs and 13 housekeeping genes in RNA samples from 150 patients with PT-DLBCL were sequenced using next-generation sequencing technology. After quality-control, CPM standardization, and normalization, microRNA profiling data were obtained for 113 patients with PT-DLBCL. Our analysis identified a microRNA signature (comprising 35 microRNAs) that clustered 113 patients with PT-DLBCL into two distinct clusters. Patients with high expression of 16 microRNAs (miR-514a-3p, miR-202-3p, miR-509-5p, miR-509-3-5p, miR-506-3p, miR-508-3p, miR-514b-5p, miR-513a-5p, miR-510-5p, miR-513b-5p, miR-513c-5p, miR-508-5p, miR-509-3p, miR-202-5p, miR-507, and miR-514b-3p) had significantly better survival.