Electric power steering is developed to reduce effort by providing steering assist to the driver of a vehicle. In recent years, a research regarding returnability is performed in order to improve driver's steering feeling. Returnability is affected to friction force in EPS system and reaction force through tire and rack. Usually in the EPS system, friction and Reaction force are uncertain components which are hard to measure. This paper introduces both estimation using sliding mode observer and control algorithm using input disturbance compensation for returnability of EPS system. And simulation confirms the results of the estimation and control algorithm.