A model for the subthreshold current and subthreshold swing of fully depleted short-channel Si-SOI-MESFETs is presented in the paper. The subthreshold current of the device is modeled empirically by an exponential function of gate-source and drain-source voltages. The short-channel effects have been included in terms of some empirical constants in the model which have been finally derived from the two-dimensional potential distribution function of the device. The subthreshold swing characteristics of the device are obtained using the subthreshold current model. The validity of the proposed model is shown by comparing the theoretical data with the simulation results obtained by using the ATLAS (TM) device simulation software. (C) 2008 Published by Elsevier Ltd.