With a view to modelling the Au-In-Sn alloy system, the enthalpies of mixing of liquid Au-In-Sn alloys have been measured as a function of Au content by drop calorimetry at 609 degrees C for constant In:Sn ratios of 1:1, 1:3 and 3:1. For each of the three sections studied, the enthalpies of mixing were exothermic. In addition, the enthalpy of formation of the ternary Au4In3Sn3 at 298 K was measured both by direct-reaction calorimetry and by tin-solution calorimetry. (C) 2010 Elsevier B.V. All rights reserved.