The present invention relates to an adjustable camshaft (1) in which an inside shaft (4) is rotatably mounted with respect to an outside shaft (2). To create a relative rotational movement between the two shafts (2, 4), a hydraulic regulating device (3) is provided at one end of the camshaft (1) and a chain/belt wheel (7) that is connected to a drive, in particular to a crankshaft, via a chain or a belt is also provided. It is essential to the invention here that the chain/belt wheel (7) is designed so that it is rotatable in relation to the regulating device (3) for aligning the camshaft (1) with respect to the drive, and after successful alignment, it is connectable in a rotationally fixed manner to either the inside shaft (4) or to the outside shaft (2).