A system for controlling locomotion of a legged such as a biped walking robot having a body and two legs connected to the body. Positional walking data are preestablished in advance with respect to the robot's center of gravity, foot position and the like. First, a difference between the robot's center of gravity at time t (current time) and at time t+delta t (next time) defined in the walking data is calculated. From the difference, then, a positional correction amount of the robot's hip position, which is decisive for determining the robot's attitude, at the time t+delta t is determined, and the robot's attitude at the time is determined from the corrected hip position and the foot position or the like preestablished in the walking data. And based on the determined attitude at the time, target joints angles of the robot is calculated and the joints are driven to the determined target angles. Since the walking data are preestablished in terms of the positional information, locomotion can be modified as required during walking. In another embodiment, forces acting on the robot legs are detected to estimate the robot's center of gravity at the current time (time t). The estimated value is used to determine the difference to be used to determine hip position correction amount which is in turn used in the robot's attitude.