In this study, a linear seven degrees of freedom vehicle model is used in order to design and check the performance of Sliding Mode Controlled Active Suspensions. Force Actuators are mounted as parallel to the four suspensions and a non-chattering control is realized. Sliding Mode Control is preferred because of its robust character since any change in vehicle parameters should not affect the performance of the active suspensions. Improvement in ride comfort is aimed by decreasing the amplitudes of motions of vehicle body. Body bounce, pitch and roll motions of the vehicle are simulated both in time domain in case of travelling on a limited ramp type of road profile and frequency domain. Also phase plane plots of them are checked. The robustness of the controller has been proved by using different vehicle parameters such as vehicle mass and damper ratios. Simulation results are compared with the ones of passive suspensions.