The quality-of-service (QoS) communication that supports mobile applications to guarantee bandwidth utilization is an important issue for Bluetooth wireless personal area networks (WPANs). In this paper, we address the problem of on-demand QoS routing with interpiconet scheduling in Bluetooth WPANs. A credit-based QoS (CQ) routing protocol is developed which considers different Bluetooth packet types because of different types of Bluetooth packets have different bandwidth utilization levels. This work improves the bandwidth utilization of Bluetooth scatternets by providing a new interpiconet scheduling scheme. Centralized and distributed algorithms are investigated in this work to improve the bandwidth utilization for the on-demand QoS routing protocol. The performance analysis illustrates that our credit-based QoS routing protocol achieves enhanced performances, compared to existing QoS routing protocols.