The present invention relates to an adjustable camshaft in which an inside shaft and an outside shaft, each being fixedly connected to cams, are mounted so they are rotatable in relation to one another. To produce the relative movement, a hydraulic adjusting mechanism is provided on one of the ends thereof; in the adjusting mechanism, first and second rotatable adjusting elements are each fixedly connected to one of the two shafts opposite one another. Adjacent to the adjusting mechanism, the outside shaft is fixedly connected to a first bearing ring supporting at least the outside shaft in a stationary first abutment. Alternatively, it is essential to the present invention either that the first adjusting element is supplied with hydraulic medium via hydraulic channels running in a second abutment and a second bearing ring or a pressure bearing disk is provided with corresponding hydraulic channels between the adjusting mechanism and the first abutment, the hydraulic channels supplying hydraulic medium to the second adjusting element.