A camshaft adjuster for adjusting the relative angular positions of a camshaft and a crankshaft of an internal combustion engine in accordance with a setting shaft is provided. In which the setting shaft is driven by a setting assembly and has a driving connection with an adjusting gear through a coupling. The drive moment is transmitted in the coupling by a radial extension (21) of a first coupling half (19), which contacts a second coupling half (25) without play in a circumferential direction and which is movable in a direction of a Y-Y axis relative to a second coupling half (25). This permits compensation of eccentricities between the setting shaft of the setting assembly and the adjusting gear.