This paper presents the effect of five dissolved inorganic salts (sodium chloride, NaCl; calcium chloride, CaCl,; zinc chloride, ZnCl(2); cadmium chloride, CdCl(2); ammonium chloride, NH(4)Cl) on the enthalpy of mixing (HE) of the binary system ethanol + pyridine measured at 303.15 K using an isothermal displacement calorimeter with vapor space. Compared to the salt-free system, the addition of selected salts (0.05 mass fraction) significantly increased the HE values along the negative direction in the order of ZnCl(2) > NaCl > CdCl(2) approximate to CaCl(2) > NH(4)Cl. With increasing salt concentration (0.10 mass fraction), the H(E) values decreased in the positive direction for the salt CdCl(2) and increased in the negative direction for the salt CaCl(2) which exemplifies the importance of solute-pyridine interaction. The experimental values of HE were fitted into the Redlich-Kister equation, and the deviations from the ideal value and binary parameters are reported.