Large-scale competitive P2P networks are threatened by the non-cooperation problem,¹ where peers do not forward queries to potential competitors. Non-cooperation will be a growing problem in such applications as pay-per-transaction file-sharing, P2P auctions, and P2P service discovery networks, where peers are in competition with each other to provide services. Here, we show how non-cooperation causes unacceptable degradation in quality of results, and present an economic protocol to address this problem. This protocol, called the RTR protocol, is based on the buying and selling of the right-to-respond (RTR) to each query in the network. Through simulations we show how the RTR protocol not only overcomes non-cooperation by providing proper incentives to peers, but also results in a network that is even more effective and efficient through intelligent, incentive-compatible routing of messages.