We evaluate the electronic contribution to the pressure dependence of the bulk modulus B of pure metals using an effective jellium. model to characterize the electronic density. The partial derivative n=partial derivativeB/partial derivativeP evaluated at zero pressure (and at constant temperature) is the main parameter on which the Murnaghan equation of state depends. The general features of this method are discussed and the corresponding results are compared with experimental data. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.