The development of hydroelastic engine mounts has resulted in ride performance superior to that of conventional all-rubber mounts. Therefore, they have been widely applied to ears recently. However, their vibration transmission mechanism has yet to be thoroughly explained.By theoretical analysis of this mechanism, it is found that these mounts function as a “Velocity Amplifying Dynamic Damper”. It was also found that by making effective use of this function that the resonance of the mount can be tuned to an extremely low frequency range while still maintaining a compact structure. At the same time, the vibration damping effect can also be improved.Applying these results to an analysis of riding comfort, an optimum application method for hydroelastic engine mounts is obtained.