[Subject]To rapidly rise a temperature of lubricant in a transmission housing of a hybrid drive power apparatus when the lubricant temperature is lower than a preset lower limit value.[Solution]A control system of a hybrid drive power apparatus of the type which comprises a transmission housing provided therein with a first input shaft to be applied with drive power from an engine through a first friction clutch and a second input shaft to be applied with the drive power of the engine through a second friction clutch, first and second gear-shift mechanisms respectively assembled with the first and second input shafts, a final output shaft in drive connection with each output shaft of the gear-shift mechanisms, a motor-generator in drive connection with the first input shaft or the second input shaft, and a driven mechanism in drive connection with the final output shaft, wherein the control system includes a temperature sensor for detecting a temperature of lubricant stored in the transmission housing, and control means for selecting a shift-step in the first or second gear-shift mechanism assembled with the input shaft in drive connection with the motor-generator when the lubricant temperature detected by the sensor is lower than a preset lower limit value so that drive torque larger than that required for driving the driven mechanism is transferred to the final output shaft, for activating the motor-generator as an electric motor after selection of the shift-step , and for engaging the first or second friction clutch so that the drive torque of the engine is transferred to the final output shaft through a gear set at the selected shift-step in the first or second gear-shift mechanism.