A method for operating a hybrid drive system, in particular of a motor vehicle, having at least one electric machine and one internal combustion engine, a disconnecting clutch being provided between the electric machine and the internal combustion engine and a torque converter having a turbine wheel being provided between the electric machine and a hybrid drive output, the disconnecting clutch being engaged for starting the internal combustion engine. It is provided that, as a function of the rotational speed of the turbine wheel of the torque converter, a rotational speed is predefined for the electric machine such that no sudden torque change occurs at the hybrid drive output when the internal combustion engine is started.