Inhibitors of phosphodiesterase type 5 are the first line in the treatment of erectile dysfunction. Recent publications indicate ambiguous influence on spermatogenesis – from stimulating up to contraceptive. In spite of high selectivity all inhibitors of type 5 phosphodiesterase effect on other PDE isoferments, located in different tissues, including PDE type 11. In experiments the influence of that particular isoferment in spermatogenesis regulation was proved. Despite of big quantity of researches of influence of inhibitors of PDE type 5 on spermatogenesis scientists do not have a unified opinion. According to several researchers the influence of inhibitors of PDE type 5 (e.g. sildenafil) on sperm cells mobility depends on concentration of the drug. Authors also report that prescription of inhibitors of PDE type 5 enforces sexual stimulation that leads to increase of prostate secretory function. Exactly by this factor authors explain increase of active sperm cells, mobility quality increase, increase of morphologically normal cells ratio. Considering the importance of male infertility problem and high notability and wide spread of PDE type 5 inhibitors a thorough analysis of its influence on spermatogenesis is on demand. Thereby the comparative analysis of this drug types allows to work out specific recommendations of inhibitors of PDE type 5 in active males.