This paper applies the concept of the output frequency response function (OFRF) derived recently by the authors to analyse the effects of the nonlinear damping characteristic parameters in a MR damper on the output frequency response of a single degree of freedom (SDOF) vibrating system, where the MR damper is directly used to dissipate the vibration energy. The results gained from this work are of significance for the analysis and design of MR damper based vibration isolation systems.