A substrate transport apparatus including a frame, at least one arm link rotatably connected to the frame and a shaftless drive section. The shaftless drive section including stacked drive motors for rotating the at least one arm link relative to the frame through a shaftless interface, each of the stacked drive motors including a stator having stator coils disposed on a fixed post fixed relative to the frame and a rotor substantially peripherally surrounding the stator such that the rotor is connected to a respective one of the at least one arm link for rotating the one of the at least one arm link relative to the frame causing an extension or retraction of the one of the at least one arm link, where the stacked drive motors are disposed in the at least one arm link so that part of each stator is within a common arm link.