A method for controlling a motor vehicle drive train including a combustion engine, an electric machine and a transmission, which are coupled by a summation gear system, having two input and one output elements, and a clutch. One input element is coupled to the crankshaft of the combustion engine, the other input element is coupled to the rotor of the electric machine and the output element is coupled to the input shaft of the transmission and the clutch is arranged between two elements of the summation gear system, such that when the clutch is disengaged a speed difference between the combustion engine and the transmission input shaft is synchronized by the electric machine and, if necessary, by a controlled engagement of the clutch. To improve synchronization, at the beginning of the synchronization the clutch is brought to its contact point before the engagement of the bridging clutch.