An accurate model is presented to calculate the solubilities of C2H6 in pure water (273-444 K and 0-1000 bar) and in aqueous NaCl solutions (273-348 K, 0-16 bar and 0-6.3 mol kg(-1)). This model is based on a specific particle interaction theory for liquid phase and a new accurate equation of state developed in this study for vapor phase. Precision of the model is within or close to the uncertainty of experimental solubilities (about 7%). A FORTRAN code is developed for this model and can be downloaded from the website: www.geochem-model.org/programs.htm. (c) 2005 Elsevier B.V. All rights reserved.