The present invention is to provide a control system for a hybrid vehicle in which, even if during traveling of the hybrid vehicle, a battery defect arises in a high-voltage power source, battery-less emergency traveling can be achieved over a sufficiently long distance, and the steering assist force can be effectively prevented from changing rapidly during traveling. The control section includes high-voltage power source defect processing unit. During execution of a mode in which the high-voltage power source, is reduced so that the reduced voltage is supplied to an electric power steering device (EPS), when a defect occurs in the high-voltage power source, the high-voltage power source defect processing unit shifts to a mode in which the low voltage of a low-voltage power source is increased so that the increased voltage is supplied to the EPS. The high-voltage power source defect processing unit then disconnects the high-voltage power source and the driving circuit from each other. Thereafter, the control section shifts to a mode in which a voltage corresponding to power generated by a generator is reduced so that the reduced voltage is supplied to the EPS, while allowing the generator to drive a traveling motor.