This paper looks into the feasibility of a hydraulic regenerative suspension system for vehicles. The linear motion from vehicle vibration is converted into rotational motion by using a double-acting hydraulic cylinder, a hydraulic motor and associated hydraulic system. The rotational motion drives an electrical generator, converting mechanical energy into electrical energy. The energy recovery system was designed, constructed, and tested in lab and on an all-terrain-vehicle (ATV). While the average power output and efficiency were not as high as expected, several paths for future improvement were discovered. It appears that the sizing of components in this small scale system is critical to achieve more desirable power outputs and efficiencies.