A mesochronous bus to reduce the peak I/O power dissipation is proposed. In the proposed bus, subsets of bus lines have nonoverlapping bus transitions in every clock cycle. Experimental results with 0.18 mum libraries show that it outperforms other systems for a wide range of bus frequencies. The reduction rate for a typical 32 bit, 33MHz bus is 90.6%, which is an 81.3% improvement over the previous work.