This paper presents an analytical method to simultaneously determine the complex characteristic impedance and the pad parasitics of transmission lines fabricated on silicon. The method uses experimental two-port network parameters of two lines differing in length without the need of a reflect standard such as that required in TRL-like formulations. Furthermore, the losses associated with the silicon substrate are accurately considered using the experimentally determined complex propagation constant of the lines and three different configurations for the pad parasitics can be assumed. When using the extracted parameters in a model to represent transmission lines, excellent agreement between simulated and experimental data was achieved up to 50GHz even for lines with lengths different to those used in the determination process. (C) 2009 Elsevier Ltd. All rights reserved.