A drive train (1) of a motor vehicle has an internal combustion engine (2) with a crankshaft (6). A transmission (3) is connected downstream of the internal combustion engine (2) to drive at least one axle (5) of the motor vehicle. A starter generator (23) is assigned to the internal combustion engine (2). The starter generator (23) is attached to the crankshaft (6) by two separate drive trains (13, 22; 24, 25). One (24, 25) of the drive trains (13, 22; 24; 25) has a shiftable clutch (29) and the other (13, 22) of the drive trains (13, 22; 24, 25) has a shiftable clutch (32) or a freewheel (11) that is active during a starter mode of the starter generator (23). The drive train ensures an optimum start capability of the cold internal combustion engine and additionally permits electric boosting of the internal combustion engine.