Disturbances of fertilizing potential of spermatozoa are closely associated with dysfunction of ion-transporting ATPases, in particular Ca 2+ , Mg 2+ -АТРase. Reduced activity of tapsigargin-resistant and tapsigargin-sensitive Ca 2+ , Mg 2+ -АТРase leads to disruption of Ca 2+ -homeostasis and is characteristic for abnormal spermatozoa (pathoospermia). In order to study the peculiarities of action of Ca 2+ , Mg 2+ -АТРase, we determined the initial reaction rate, the maximum (plateau) amount of the reaction product and the characteristic reaction time. To determine these kinetic parameters of Ca 2+ , Mg 2+ -dependent hydrolysis of ATP catalyzed by Ca 2+ , Mg 2+ -ATPase, the dynamics of product accumulation of the ATP-hydrolases reaction was studied. The obtained curves were linearized in the coordinates { P / t ; P }. Analyzing the changes in the activity of Ca 2+ , Mg 2+ -ATPase, the kinetics of primary-active transport of calcium ions through the plasma membrane and membranes of intracellular Ca 2+ -stores in saponin-permeabilized spermatozoa of infertile men was studied. It was shown that in normozoospermic samples, the transport of Ca 2+ ions through the plasma membrane is characterized by a higher capacity than through the membranes of intracellular Ca 2+ -stores, but it occurs with practically the same initial velocity and characteristic reaction time. It was found that in pathospermic samples, transport of Ca 2+ ions with the participation of both components of Ca 2+ , Mg 2+ -ATPase occurs less intensively and is characterized by a lower capacity compared to spermatozoa of men with preserved fertility. Specific changes in the kinetic parameters of Ca 2+ , Mg 2+ -dependent hydrolysis of ATP lead to inhibition of tapsigargin-resistant and tapsigargin-sensitive Ca 2+ , Mg 2+ -ATPase activity and cause a decrease in fertilizing potential of spermatozoa. Keywords : Ca 2+ , Mg 2+ -ATPase, ATP hydrolysis, spermatozoa, male infertility, pathospermia