Different equations were employed to calculate vaporization enthalpy of pure substances. The normal point of boiling was used as the reference for all of them. Specifically, for the method of [A.G. Meyra, VA. Kuz, G.J. Zarragoicoechea, Fluid Phase Equilib. 218 (2004) 205-207], three different values of critical universal ratio (Z(c)) were tested in order to verify the influence of the existing theories in the calculation of the desired property. It was observed that the behavior of the vaporization enthalpy with the temperature is not universal, as some researchers have believed. In the present work we are showing that all the equations provided the same deviation dispersion when it tried to correlate the experimental data. (c) 2005 Elsevier B.V. All rights reserved.