For a long time, in practice, and science, has been known that pH values of sperm and vagina are important for successful fertilization. In this investigation this fact was confirmed, and the goal was to investigate the role of pH values through whole reproductive tract of male and female individuals: testis, rete testis, epididymis, ductus deferens, Cowper's gland, vesicula seminalis, prostata, corpus cavernosus, corpus spongiosus, epitel tissue of penis tube, sperm, vagina, uterus, horn of uterus, oviduct, fimbrie ovarica, ovarium, follicular fluid. Measurement was performed in reproductive active males as well as before and after ovulation in females. Porcine reproductive tracts (per 15 female and male individuals) were collected from institute's slaughterhouse, immediately post mortem dissected, homogenised and pH values were measured (according to method Rede&Rahelic (1969)). Ovarium and follicular liquid have the highest pH values (7,4) in females, but a small peak in preovulatory oviduct is also present and corresponded to pH of sperm of reproductive fully active male individuals (pH=app.7,2). After fertilization pH in surrounding of zygot (through depolarisation of its membrane) in oviduct, and zygot which then has external decreased pH value moves to less pH values regions by the same principle, that means to uterus, (pH between 7,2 (horn) and 7,07(cervix)) in postovulatory female reproductive tract, where nidation of blastocyst occurs. This investigation could help to elucidate knowledge about reproductive physiology in vivo, giving importance to role of pH values along reproductive tract of male and female individuals.