We examine the utility of the virial equation of state (VEOS) for the prediction of the solubility of hexane in supercritical carbon dioxide. We computed virial coefficients up to fourth-order for this mixture at 353.15 K, using Mayer-sampling Monte Carlo applied to established molecular models for carbon dioxide and hexane. At this temperature, neither the third- nor fourth-order VEOS indicate the presence of a critical point for the mixture. However, the VEOS coupled with an ideal-solution treatment for the coexisting subcritical fluid phase (with parameters determined from coexistence data at one pressure) reproduces much of the solubility curve as previously established by Gibbs-ensemble molecular simulation. Comparison of the third- and fourth-order VEOS indicate that the virial treatment is converged at the conditions where it is applied. (C) 2010 Elsevier B.V. All rights reserved.