A mathematical model of viscous fluid flow in the gap of a disk pump with nonplane disks has been developed. The characteristics of the pump — flow velocity, pressure drop, stress tensor, and the hydraulic coefficient of pump efficiency — have been calculated. A local pressure minimum in the pump has been detected, which leads to local ″choking″ of flow and to a decrease in the pressure characteristics and in the pump efficiency. The parameters causing the local ″choking″ of flow have been found, and the means of overcoming this phenomenon are indicated. An optimum inner radius of the disk at which maximum pressure drop and efficiency of the disk pump are achieved has been established, which made it possible to calculate the optimum parameters of the pump′s disk packet.