Four types of human T cell lymphotropic viruses (HTLV) have been described (HTLV-1 to HTLV-4) with three of them having closely related simian virus analogues named STLV-1, −2, and −3. To assess the risk of cross-species transmissions of STLVs from nonhuman primates to humans in the Democratic Republic of Congo, a total of 330 samples, derived from primate bushmeat, were collected at remote forest sites where people rely on bushmeat for subsistence. STLV prevalences and genetic diversity were estimated by PCR and sequence analysis of tax-rex and LTR fragments. Overall, 7.9% of nonhuman primate bushmeat is infected with STLVs. We documented new STLV-1 and STLV-3 variants in six out of the seven species tested and showed for the first time STLV infection in C. mona wolfi, C. ascanius whitesidei, L. aterrimus aterrimus, C. angolensis, and P. tholloni. Our results provide increasing evidence that the diversity and geographic distribution of PTLVs are much greater than previously thought.