Activity coefficients of acetamide in acetamide-calcium nitrate melt solutions were determined from cryoscopic data in the concentration range O to 0.151 mole fraction of calcium nitrate. Enthalpies of melting and melting point depressions were obtained from DSC measurements. Melt solutions were obtained from two crystalline forms of acetamide. Eutectic formation was observed in both crystalline forms. Heat capacity of pure acetamide in the two forms was measured in the temperature range 20 to 100°C. Activity coefficients obtained for molten acetamide from two sets of cryoscopic data were in good agreement. Change of activity coefficients with calcium nitrate concentration indicate strong association between solvent and solute and ‘water-like’ acting of molten acetamide.