A drive system of a hybrid vehicle, including an engine, a first electric motor, a second electric motor operatively connected to a drive wheel of the hybrid vehicle, and two planetary gear mechanisms, and wherein the two planetary gear mechanisms have at least four rotary elements arranged to permit the drive system to be placed in a selected one of a first operation mode in which the rotary element connected to the engine and the rotary element connected to the first electric motor are disposed on opposite sides of the rotary element connected to the drive wheel and the second electric motor, as seen in a collinear chart in which the four rotary elements are located at respective four different positions along a base line, and a second operation mode in which the rotary element connected to the first electric motor and the rotary element connected to the drive wheel and the second electric motor are disposed on opposite sides of the rotary element connected to the engine, as seen in said collinear chart.