A new model for predicting the viscosities of biodiesel is presented in this work. This model is based on the principle of corresponding states, using one- and two-reference fluids. For the critical constants of methyl esters, the Marrero-Gani method was used. For biodiesels, Lee-Kesler's mixing rules were used for critical constants calculations. The two models studied in this work were compared with Ceriani et al. [5], Yuan [6], and Revised Yuan [7] models. A set of data on biodiesel viscosity was used in this work, consisting of 31 pure biodiesels and 4 mixtures of biodiesel (totalizing 193 experimental data). The best result was found using a two-reference-fluids model, methyl laurate (C12:0) and methyl oleate (C18:1), with a global average relative deviation of 6.66%. (C) 2011 Elsevier Ltd. All rights reserved.