There is disclosed a conveyor drive roller of the type which may be used for example for supporting and driving a conveyor medium. The conveyor drive roller has a hollow drum which defines a cylindrically shaped rotatable supporting surface, and an internal surface. The hollow drum is rotatably connected to a first and a second support structure. An internal gear assembly is disposed inside of the hollow drum and operably connected to the internal surface of the hollow drum. The second support structure is adapted to permit a rotor of a motor located outside of the hollow drum to releasably couple to the internal gear assembly through the second support structure, so that when the rotor is coupled to the internal gear assembly, through the second support structure, rotation of the rotor is transmitted by the internal gear assembly to the hollow drum to cause rotation of the hollow drum about the first and second support structures.