Control methods for multi-phase machine drives under open-phase fault condition are commonly designed to achieve minimum torque ripple. These methods are usually based on machine fault model. Therefore, it is highly model dependant. In this article, a new robust control method for six-phase induction motors (SPIM) under open-phase fault condition is proposed. Design of ADRC is independent of the controlled system model and machine parameters. This method has been proposed for the first time for multi-phase machines in the post-fault situation. There is no need to change control structure for post-fault operation and machine control in faulty condition is carried out without need to fault detection. Performace of ADRC in healthy and faulty situations are compared with PI and resonant (dual PI) controllers. Simulation results on a six-phase induction motor are presented for verification of the proposed control scheme. It can be seen the six-phase induction motor drive shows better performance when it works with ADRC in both healthy and faulty operation modes.