A three-parameter corresponding states (CS) model is developed, importing methods formerly studied for the volumetric representation Of fluids. The three parameters are critical temperature, pressure and a viscosity scaling factor psi defined from experimental saturated liquid viscosity data or, when these are unavailable. from a single experimental point. Two reference fluids are chosen both for their psi factor value and because the corresponding viscosity dedicated equations (VDE) are available. On the basis of the three-parameter CS model proposed by Teja et al. for volumetric properties, the reduced viscosity of a third fluid is obtained in reduced P. T variables interpolating that of the two reference fluids, calculated at the same reduced temperature and pressure, by psi. Where the transport property is known along the saturation line at least, an improvement is introduced by correcting the psi factor with a temperature-dependent function fitted on these data. The model is then extended to mixtures using the one-fluid model approach, in a completely predictive mode with respect to the mixture. The accuracy for both pure fluids and mixtures is comparable with that of the reference fluids' equations, while in the unimproved and improved mode the amount of input data is very limited. Also, comparison with a four-parameter CS model and with an ECS model confirms the accuracy of the present technique. Considering the predictive nature of the model and the scattering of the available experimental data, the mean accuracy is good and more than satisfactory for the purposes of technical applications. Copyright (C) 2002 John Wiley Sons, Ltd.