In this paper, we present a simple and effective solution for resolving the in-device coexistence problem of Wi-Fi and Bluetooth. The main idea is to introduce a canceller in the circuit in order to cancel out the in-device interference when Wi-Fi and Bluetooth radios simultaneously operate in the same device. Our proposed approach, entitled the hybrid arbitrator, can significantly improve the performance of both of Wi-Fi and Bluetooth. Based on our testbed, we carry out extensive experiments to validate the performance of the proposed scheme. Our results show that the proposed hybrid arbitrator gives substantially better performance than existing methods.