In many database applications, there are opportunities for multiple top-N queries to be evaluated at the same time. Often it is more cost effective to evaluate multiple such queries collectively than individually. In this paper, we propose a new method for evaluating multiple top-N queries concurrently over a relational database. The basic idea of this method is region clustering that groups the search regions of individual top-N queries into larger regions and retrieves the tuples from the larger regions. This method avoids having the same region accessed multiple times and reduces the number of random I/O accesses to the underlying databases. Extensive experiments are carried out to measure the performance of this new strategy and the results indicate that it is significantly better than the na