Induction of human sperm chemotaxis is an established phenomenon, though signaling systems physiologically involved have not been identified. Recently, it has been demonstrated that RANTES is present in the follicular fluid and that this molecule is a chemoactractant for human spermatozoa. However, the presence of beta-chemokine receptors on human spermatozoa has never been reported. By cytometric, Western blotting and immunofluorescence analysis, we demonstrate the presence of CCR5 and CCR3 on ejaculated spermatozoa from healthy subjects. CCR5 was detected in the periacrosomal region of the sperm surface, whereas CCR3 was also present in the postacrosomal cap. Individual variability was observed on CCR5 and CCR3 positive sperm percentages. Presence of Delta32+/-) mutation was demonstrated in two subjects expressing CCR5 in half of the ejaculated spermatozoa. Our findings represent the missing information in favor of the possibility that beta-chemokines and their receptors are involved in sperm chemotaxis. Identification of molecular mechanisms of sperm chemotaxis may allow us to identify predictive parameters of sperm fertilizing ability in hypofertile or infertile subjects. Finally, both CCR5 and CCR3 expressed on the sperm cell surface may be involved in HIV-1 adhesion to spermatozoa, thus allowing these cells to perform as virion cellular carriers during sexual transmission of HIV-1 infection.