With retrograde ejaculation, the ejaculation mechanism changes: the expulsion of the seed fluid occurs in the proximal direction into the bladder.The aim of the research. Identification of the value of determining the concentration of prostate specific antigen (PSA) in post-orgasmic urine (POM) for the diagnosis of retrograde ejaculation.Materials and methods. 59 men (age 34,1 ± 8,9 years) were examined. The main group (n=27) consisted of men suffering from retrograde ejaculation. The comparison group (n=32) included men whose ejaculation was physiologically antegrade and who had no coitus during the previous 2 days. The concentration of total PSA in blood serum and urine was determined by solid-phase enzyme immunoassay (ELISA) using the test system "total PSA-ELISA-BEST" (T-8458) (Vector–Best LLC, Russia).Results. The median concentration of total PSA in urine in the comparison group was 9,52 times higher than the same indicator in blood serum. When comparing the content of total PSA in the main group of patients in the morning urine, in the 1st (at the beginning of the act of urination) and 2nd (at the end of the act of urination) portions of POM, we found comparable indicators of the concentration of total PSA, no significant differences were found (the Kraskel–Wallis criterion H=0,4914, p=0,9208, with a pairwise comparison between all the studied groups of urine samples, p = 1,000000).Conclusion. The level of PSA in the urine of men of fertile age is almost 10 times higher than that in blood serum. The presence of PSA in high concentration in the bladder urine may indicate various ways of getting this substance into the urine: retrograde casting of sperm during ejaculation and free filtration of this protein in the glomeruli of the kidney. The PSA total urine test is not suitable for laboratory diagnosis of retrograde ejaculation.