Activity coefficients of NaCl in water + methanol + ethanol solutions have been determined from electromotive force (emf) measurements at 298.15 K. We have used a cell [ISE Na+\NaCl, H2O, MeOH, EtOH\ISE Cl-] to obtain the emf of eight mixture series containing 10 to 40 (w/w) of methanol + ethanol at molalities up to 2.0 of NaCl. A modified Pitzer equation is used together with the Nernst equation to obtain the mean activity coefficient.