In this paper, fault detection and tolerance in static walking of legged robots are addressed. A kind of fault events, locked joint failure, is defined and its properties are investigated in the frame of gait study and robot kinematics. For the purpose of tolerating a locked joint failure, an algorithm of fault tolerant gaits for a quadruped robot is proposed in which the robot can continue its walking after a locked failure occurs to a joint of a leg. A case study on applying the proposed scheme to wave gaits verifies its applicability and capability.