A simple group contribution method to predict the glass transition temperature of several ionic liquids is present. Experimental data of 150 ionic liquids were taken from the literature and used to obtain the contributions for the cation-anion groups in a correlation set. The optimum parameters of the method were obtained using a genetic algorithm-based on multivariate linear regression. The capabilities of the designed method were tested in the prediction of the glass point of another 100 ionic liquids not used in the correlation step. The results show that the group contribution method represents an excellent alternative for the estimation of the glass transition temperature of diverse ionic liquids from the knowledge of their molecular structure with an average deviation of 5% and a correlation coefficient of 0.91. (C) 2011 Elsevier B.V. All rights reserved.