This paper describes the design and development of a 6 degree of freedom robotic manipulator used in the assembly of three-dimensional MEMS (micro electromechanical systems) microstructures. The robot employs a highly innovative mechanical design for the rotational axes to provide unprecedented access to a microchip substrate for microassembly operations. The first three axes of the robotic manipulator are orthogonally mounted linear stages providing Cartesian positioning of the chips beneath the end effector (microgripper). A rotational stage (alpha) mounted on the distal end of these three Cartesian axes allows the MEMS chip to be rotated. Two more degrees of freedom (beta and gamma) are serially mounted to the base frame, allowing for two degrees of rotation of the end effector. This configuration permits assembly of micro-parts on the surface of a MEMS chip at any orientation angle to the surface, within the limits of the workspace of the manipulator and the resolution of the motors. The end effector employs a standard tungsten probe with a passive microgripper bonded to it, which is used for grasping micro-parts. A software system has been developed to allow automatic operation of the manipulator. Preliminary assembly tests confirm the usefulness of the proposed design