The effect of five dissolved salts (sodium chloride, calcium chloride, zinc chloride, cadmium chloride, and ammonium chloride) on the enthalpy of mixing of the binary system 1,4-dioxane + acetic acid has been investigated at 303.15 K in an isothermal displacement calorimeter with vapor space. A decreasing trend in excess enthalpy for the salts NH4Cl and NaCl but an increasing trend for the salts CaCl2, ZnCl2, and CdCl2 with increasing salt concentration was observed. The Redlich-Mster equation has been used to fit the experimental enthalpy of mixing data, and the binary parameters have been estimated.