A tunable hydraulic mount has been designed to overcome the limitations in hydraulic mounts. The tuning of the new hydraulic mount is acheived by incorporating electro-rheoiogical fluids (ER fluids) into the mount. The design of the tunable ER fluid mount allows the stiffness resonances and anti-resonances to be tuned to several discrete frequencies. Mount models have been derived and the models have been validated by comparing simulated and measured results. These results demonstrate the mount versatility in specific applications and in studying the performance of a suspension system using hydraulic mounts.