In order to execute the global issue mandated for an environmentally friendly vehicle, research on the hybrid electric vehicle (HEV) has been developed in the Mechanical Engineering Department of Universitas Indonesia (MED-UI). The ultimate goal of this research is simply to develop a low-cost HEV which uses energy most efficiently. A small-sized HEV seating one to two passengers has been the main focus towards completing this ultimate goal. Five prototypes in ten years have been developed, and Prototype III is one of the most inventive. The major features of this prototype are the power take-off system, frame design and the control system.