An adjustable camshaft may include an inner shaft and an outer shaft arranged coaxially thereto. The camshaft may also include a camshaft adjuster having a stator connected to the outer shaft in a torque-proof manner, and a rotor connected to the inner shaft. The camshaft may further include an integral first connection contour provided at an end of the inner shaft, and an integral second connection contour complementary to the integral first connection contour and provided on the rotor. The connection contours may directly or indirectly enable an interlocking connection between the inner shaft and the rotor.