Apparatus for damping torsional vibrations in the power trains of motor vehicles has a first flywheel connected to the crankshaft of the engine and a second flywheel which is rotatable relative to the first flywheel and can be coupled to the input shaft of the change-speed transmission by a friction clutch. Angular movements of the flywheels relative to each other are opposed by a hydraulic damper, by an elastic damper and by a friction generating device. The hydraulic damper has pairs of chambers for a viscous fluid medium which is caused to flow from one chamber to the other chamber by way of one or more flow restrictors in response to angular movements of the flywheels relative to each other.