This paper develops an adaptive actuator failure compensation control scheme for a parallel manipulator robotic system. The adaptive control design uses an integration of multiple failure compensator controllers designed for each actuator failure pattern. Such a design effectively utilizes the actuation redundancy in the unique structure of parallel manipulator systems to compensate for possible actuator failures with no knowledge of actuator failure pattern, failure time instant and failure values. With complete parameterization of system and actuator failure uncertainties and direct adaptation of controller parameters, the adaptive control scheme guarantees desired closed-loop stability and asymptotic output tracking, despite certain actuator failures. Simulation results verify the desired control system performance for a 2-DOF redundantly actuated parallel manipulator.