Aim. To assess the role of serum and ejaculate inhibin-activin status disorders in the development of reproductive disorders at idiopathic male infertility. Methods. The research includes data of laboratory and clinical examination of 82 infertile and 60 fertile men. Serum and semen levels of reproduction regulatory peptides inhibin B and activin A were determined using standard commercially available kits for enzyme-linked immunosorbent assay. Other parameters of ejaculate were also investigated. Results. In men with infertility of the unknown cause, sperm cell concentration was significantly decreased, and the proportion of sex cells with morphological anomalies was increased. The main features of inhibin-activin profile of biological fluids in healthy males with proven fertility were revealed, which were the significant gradient of inhibin and activin intertissue concentrations and domination of these molecular fertility factors in seminal plasma, corresponding with the views of their key role in sperm fertilizing capacity. In patients with pathospermia, the significant decrease of inhibin B concentration in the ejaculate but not in serum, associated with increased activin A levels was revealed, accompanied by characteristic shift of inhibin-activin ratio associated with the deterioration of quality and quantity parameters of semen. Conclusion. Revealed changes in the inhibin-activin sperm plasma mirror may be a pathogenetic basis for the idiopathic infertility in couples. Inhibin-activin coefficient in blood serum and seminal fluid may be used as a promising diagnostic and prognostic marker of reproductive dysfunction risk.