A model has been developed for the calculation of the surface tension (gamma) and its temperature dependence (d gamma/dT) for commercial alloys (steels and nickel-based superalloys) from (i) the chemical composition and (ii) values of the surface tension and molar volume of the various elemental components. The model was found to give values which were within 6% of the measured values for steels and the (d gamma/dT) results were similar to measured values. Although there are more difficult problems to be overcome with Ni-superalloys, the model predictions appear to be within 5% of the measured values. (C) 2005 Springer Science + Business Media, Inc.