The shift-and-ratio method has been considered as one of the most accurate and consistent techniques for extracting the effective channel length of the MOS transistors. The use of original shift-and-ratio method for L-eff extraction of MOS transistors with halo/pocket implants results in systematic errors for L-eff. In this paper a modification of the original method is proposed and its effectiveness is assessed through simulation. The values of L-eff extracted by the proposed method are more reasonable than those obtained using the original shift-and-ratio method. (C) 2004 Elsevier Ltd. All rights reserved.