-This paper presents an efficient method, based on the transfer function simulation method, for the transient analysis of lossy and dispersive transmission lines terminated by nonlinear circuits. This method combines the efficiency provided by rational function approximation with the accuracy of using modal decomposition. For the task of computing the convolution integral, the transfer function simulation method was found to be more straightforward for implementation and more efficient than the recursive convolution method, thus providing further improvement in simulation efficiency. A robust and efficient method for the analysis of frequency dependent (dispersive) transmission lines is also reported. This method has been implemented in AS/X, IBM production circuit simulator, and has been used routinely for the analysis of practical lossy and dispersive coupled transmission lines.