In this paper the method of stability analysis of dynamic symmetrical gaits is discussed. The problem of dynamic postural equilibrium, taking into account the role of compliant feet, is solved. The equilibrium conditions are split between the foot attachment points and the points within the foot-end area. The present method is useful for motion synthesis, taking into account robot parameters. It also helps in the robot foot design. As an illustrative example a four-legged diagonal gait is considered. The theoretical results were verified by implementing and observing the diagonal gait in four-legged machine with and without feet.