Vapor-liquid equilibrium (VLE) data of iso-propanol + iso-butanol and iso-propanol + iso-butanol + CaCl2 (at saturation) were measured at a pressure of 93.6 kPa, using a modified Malanowski equilibrium still. The VLE behavior of the salt-free system is nearly ideal with a maximum normalized excess Gibbs energy (G(E)/RT) of 0.01. The salt investigated in this work, i.e. CaCl2 shows no effect on the phase behavior of iso-propanol + iso-butanol. The experimental results of the salt-free binary were compared with those predicted by the ASOG and UNIFAC models, which predicted the bubble-point temperatures with an RMSD (root mean square deviation) of 1.01 and 1.26 K, respectively. The former model, however, predicted the vapor-phase composition within 0.012 mole fraction while the latter predicted them within 0.016 mole fraction in terms of RMSD. Moreover, two isobaric data sets (at 760 mm Hg) from the literature were analyzed using the above two models.