Although the relationship between the amount of vitamin B12 and the quality of sperm exists, but results are controversial and require several additional research. The objective of our study was to analyse the amount of vitamin B12 in the sperm samples from patients with chronic prostatitis and varicocele with accompanying asthenozoospermia, and to identify the relationship between the amount of vitamin B12 and asthenozoospermia. The research was carried out of men with chronic prostatitis and varicocele with accompanying asthenozoospermia and infertility at the age of 27±2 years. The material of the investigation was spermoplasm. A chemical microscopic examination of the ejaculate was carried out with a sperm analyzer and with the light microscopy. The amount of vitamin B12 in the spermoplasm was determined by the method of competitive ELISA. It was found that the level of vitamin B12 was 3.6 times lower in patients with chronic prostatitis III B and asthenozoospermia then in the control group. Among patients with varicocele of II and III grade and asthenozoospermia, the level of vitamin B12 was 4.4 times lower than in control group. A positive correlation relationship of average strength was revealed (r=0,683; p=0,001). Additionally, it was revealed that among patients with Chronic prostatitis III B and varicocele of II and III grades with accompanying asthenozoospermia, there was the positive correlation relationship of average strength (r=0,690; p=0,001) between the amount of vitamin B12 and sperm mobility. A decrease in vitamin B12 levels may serve as a marker of reproductive dysfunction in men.V nauchnoĭ literature imeiutsia dannye, podtverzhdaiushchie vzaimosviaz' kolichestva vitamina B12 i kachestvo spermy, no rezul'taty protivorechivy. Tsel'iu nashego issledovaniia byla kolichestvennaia otsenka vitamina B12 v spermoplazme u patsientov s khronicheskim prostatitom i varikotsele s soputstvuiushcheĭ astenozoospermieĭ i vyiavlenie vozmozhnoĭ vzaimosviazi mezhdu kolichestvom vitamina B12 i astenozoospermieĭ. Ob"ektom issledovaniia sluzhili 90 muzhchiny v vozraste 27±2 goda s diagnozom khronicheskiĭ prostatit i varikotsele s soputstvuiushcheĭ astenozoospermieĭ i besplodiem. Materialom dlia issledovaniia byla spermoplazma. Éiakuliat issledovali na spermoanalizatore i s pomoshch'iu svetovoĭ mikroskopii. Kolichestvo vitamina B12 v spermoplazme opredeliali metodom konkurentnogo IFA. U patsientov s khronicheskim prostatitom III V i astenozoospermieĭ vyiavleno snizhenie vitamina B12 v 3,6 raza po sravneniiu s kontrol'noĭ gruppoĭ. U patsientov s varikotsele II i III stepeni i astenozoospermieĭ vyiavleno snizhenie vitamina B12 v 4,4 raza po sravneniiu s kontrol'noĭ gruppoĭ. Byla vyiavlena polozhitel'naia korreliatsiia sredneĭ stepeni vyrazhennosti (r=0,683; r=0,001) mezhdu podvizhnost'iu spermatozoidov i kolichestvom vitamina B12. U patsientov s khronicheskim prostatitom III V i varikotsele II i III stepeni, soprovozhdaiushchikhsia astenozoospermieĭ, byla vyiavlena polozhitel'naia korreliatsiia sredneĭ stepeni vyrazhennosti (r=0,690; r=0,001) mezhdu podvizhnost'iu spermatozoidov i kolichestvom vitamina B12. Snizhenie urovnia vitamina B12 nizhe v spermoplazme mozhet sluzhit' markerom narusheniia reproduktivnoĭ funktsii u muzhchin.