ProAKAP4 is a sperm-specific protein recently introduced as a tool to assess sperm quality. Although not yet described in buck, proAKAP4, the precursor protein of AKAP4, is well-conserved over mammals with 79% of homology between goat and human. The aim of this study was to characterize the expression and localiza-tion of proAKAP4 in buck semen and to evaluate the correlation between proAKAP4 concentrations, motility parameters and fertil-ity outcomes after artificial insemination. Thirty-six ejaculates were collected from 18 bucks by artificial vagina in Capgènes (France) in-semination centre and diluted at 100 × 106 spermatozoa/ml before cryopreservation. Four straws per ejaculate were stored for analysis while the remaining straws were inseminated. Expression analy-sis was achieved by Western blot and electronic microscopy using monoclonal antibodies against proAKAP4 and AKAP4 (4BioDx, France). Sperm motility was assessed by computer-assisted semen analysis (CEROS). ProAKAP4 concentrations were determined by ELISA using the Goat 4MIDⓇ Kits (4BioDx, France). Fertility rates were calculated by ultrasound pregnancy diagnosis and kidding rate of the 575 goats inseminated. We showed for the first time that both proAKAP4 and AKAP4 are expressed in buck sperm. ProAKAP4 is expressed in living spermatozoa and reflects long-lasting motility. Its localization is restricted to the fibrous sheath of the principal piece of the flagellum. ProAKAP4 concentrations were positively correlated with motility parameters and goat fertility rates (Pearson r = 0.35, p < 0.01). In conclusion, as previously demonstrated in bull, horse, ram, pig and human, proAKAP4 appears as a useful indicator of sperm quality and fertility in goat.