In the present work, a new equation for estimating vaporization heat was developed by applying wagner vapor pressure equation and using the Clausius-Clapeyron equation. The new proposed equation was valid over the entire range from the triple point to the critical point for most of the substances. The vaporization heat of 76 pure liquids was calculated to verify the new equation, with the average absolute deviation 0.80%, compared with the literature values. (C) 2011 Elsevier B.V. All rights reserved.