Disclosed herein a method of controlling the balance of a walking robot. In the method, a location and an acceleration of a center of gravity of the walking robot are detected in a three-dimensional (3D) x, y, z coordinate system. A location of a Zero Moment Point (ZMP) on an xy plane is detected using the location of the center of gravity and the acceleration of the center of gravity in x- and y-axis directions. Walking of the walking robot is controlled so that the ZMP is located inside a stable area including a bottom of a foot of the walking robot on the xy plane.