In this paper, two estimation methods of cornering stiffness are proposed based on yaw-moment observer (YMO). First, a simple method is developed under the assumption that cornering stiffness coefficients of front and rear wheels are identical. A novel direct yaw-moment control (DYC) with this estimation is proposed for electric vehicles with in-wheel motors. Second, a sophisticated method is introduced which can identify the front and rear cornering stiffness independently as well as it can estimate the side-slip angle of vehicle. Simulation and experiments are carried out to show the advantages of proposed methods on various road conditions