A mobile computing system consists of mobile and stationary nodes. Checkpointing in mobile systems faces many new challenges, such as low wireless bandwidth, frequent disconnections and lack of stable storage at mobile nodes. Previously proposed checkpoint algorithms for mobile environments do not take into consideration the coordinating message overhead of the mobile participants. In this paper, we propose a new checkpoint algorithm for mobile distributed systems. Our algorithm is nonblocking and minimizes the number of checkpoint participants. We propose a new idea called proxy coordinator. By using proxy coordinator, mobile participants? coordinating message overhead is minimized to O(1), which can otherwise be as high as O(n) in other proposed algorithms.