Kisspeptin, a KISS1 gene product, stimulates GnRH neurons in the hypothalamus, but some recent studies have also suggested a direct effect on gonads. We aimed to localise Kiss and Kiss1 receptor (Kiss1r) in adult rhesus monkey testis. Experimental Procedures: Expression of Kiss1 and Kiss1r was detected in testicular tissue of rhesus monkey using immunohistochemistry and reverse transcriptase PCR (RT-PCR). Dual immunohistochemistry was used to colocalize Kiss1 with germ cell marker T4 and Kiss1r with inhibin (Sertoli cell marker) using specific antibodies for all. Immunohistochemistry of testis was conducted on formaldehyde fixed tissues using 5 ? thick sections. Using gene specific primers, RT-PCR was carried out to find expression of Kiss1 and Kiss1r mRNAs in testis. Results: Kiss1 immunoreactivity was localised to spermatocytes and spermatids and Kiss1r was observed in spermatocytes and Sertoli cells. Double-label immunohistochemistry co-localized Kiss1 and T4 in spermatids and Kiss1r and inhibin were co-localized in Sertoli cells. RT-PCR showed mRNA expression of Kiss1 and Kiss1r in adult rhesus monkey testis. Conclusions: Present results indicate for the first time the presence of Kiss1 and Kiss1r in adult primate testis. These suggest a possible autocrine/paracrine role of kisspeptin in non-human primate testis. Kiss1-Kiss1r in testis suggests possible direct involvement in the regulatory network involved in spermatogenesis. ? 2013 Versita Warsaw and Springer-Verlag Wien.