Many solutions have been proposed to tackle the problem of load balancing in structured P2P systems. However, all these solutions either ignore the heterogeneity nature of the system, or reassign loads among nodes without considering proximity relationships, or both. In this paper, we propose an efficient scheme to ensure fair load distribution in such P2P systems by utilizing proximity information. To our knowledge, this is the .rst work to utilize the proximity information to guide load balancing. In particular, our main contributions are: (1) A self-organized, fully distributed K-nary tree structure is constructed on top of a distributed hash table (DHT) for load balancing information collection/dissemination and load reassignment. (2) Load balancing is achieved by aligning those two skews in load distribution and node capacity inhere in P2P systems — that is, have higher capacity nodes carry more loads. (3) Proximity information is utilized to guide load balancing such that loads are assigned and transferred between physically close heavy nodes and light nodes, thereby minimizing the load transferring overhead and allowing load balancing to perform more efficiently.