A method of controlling a hybrid drive-train of a vehicle in which the hybrid drive-train comprises a combustion engine having a driveshaft, an electric machine that can be connected to the driveshaft of the engine by a clutch, an automated transmission with an input which is connected to the rotor of the electric machine, and shifting elements for shifting between two gears. During electric driving operation with the engine stopped and the clutch disengaged, the engine can be drag-started in combination with a downshift in the transmission. Drag starting of the engine is carried out by disengaging the frictional shifting element to be disengaged to below a slipping limit, engaging the clutch until the engine reaches or exceeds its minimum starting speed, starting the engine self-starts, substantially disengaging the clutch, separately adjusting the engine and electric machine to the synchronous speed of the target gear, and fully engaging and disengaging associated shifting elements.