The genes involved in olfactory communication in mammals via the vomeronasal system are summarized, and studies investigating these genes in primates are reviewed. Only five potentially functional vomeronasal receptor genes (V1RL s) have been found in humans, and only one of these (V1RL1) has been studied in other primates. V1RL1 has become a pseudogene repeatedly during primate evolution, but patterns of natural selection on primate V1RL genes demonstrate that this gene family diverged under natural selection throughout at least part of primate evolution. Evolution of the TRP2 gene, which encodes for an ion channel that is important in vomeronasal organ (VNO) signalling, strongly suggests that this signalling function was lost in ancestral Catarrhines. Overall, much work remains to be done to elucidate the repertoire of genes that are involved in pheromonal communication, particularly in Strepsirhines. Such studies promise unique insights into the evolution of this modality. Am. J. Primatol. 68:559–567, 2006. © 2006 Wiley-Liss, Inc.