A hydraulic camshaft adjuster (1), in particular a vane-type hydraulic camshaft adjuster, including a rotor (2) and a stator (3) which are mounted to rotate with respect to each other, a cover (10) fixed on the stator (3), including a locking receiver and at least one locking pin (11, 12) accommodated in the rotor (2), the locking pin being slidable in the axial direction and prestressed in the direction of the locking receiver, and a hydraulic channel (27, 28, 29) to apply pressure of the locking pin (11, 12) against the prestress of same, the hydraulic channel being able to be filled and emptied with a hydraulic medium via a central screw, wherein in the rotor (2) at least one additional discharge channel (37, 38, 39, 40) fluidically connected to the hydraulic channel (27, 28, 29) is formed with a discharge valve (33, 34, 35, 36), wherein preferably the discharge valve (33, 34, 35, 36) closes the discharge channel (37, 38, 39, 40) when the locking pin (11, 12) is pressurized and opens the discharge channel when the hydraulic pressure acting on the locking pin (11, 12) falls.