In this paper, we present a RC-in RC-out model order reduction method which takes RC circuits and accurate reduced models which can be realized using passive RC elements. The reduced models are accurate up to 2nd order moment and hence are more accurate than the first order moment matching based algorithm. The runtime and reduction ratios of our method are not dependent on the number of ports, which can be very large for tightly coupled interconnects. Extensive SPICE simulations show the average accuracy of our algorithm is 5/spl times/ better than first order moment based algorithms. It also significantly improves the reduction ratio by 50% comparing the first order moment based algorithm for the same accuracy.