High pressure pure component pressure-volume-temperature (PVT) properties of ionic liquids are summarized and analyzed with a Modified Cell Model (MCM) that uses characteristic parameters, T*, V* and P*. The model was found to provide good fits of 28 different ionic liquid PVT data consisted with 14 types cation and 10 types anion over a wide range of temperatures (278-473 K) and pressures (0.1-200 MPa). The characteristic parameters of the model could be correlated with simple functions of the Bondi van der Waals volume for the cation and anion of each ionic liquid. Generalized parameters for MCM with the van der Waals volume are proposed that allow calculation of ionic liquid densities at high pressures to within an average deviation of 1.9%. (C) 2009 Elsevier B.V. All rights reserved.