Isobaric vapor-liquid equilibrium (VLE) measurements at atmospheric pressure were made for 1.0-3.0 m tetrapropylammonium bromide (TPAB) and 3.0 m tetrabutylammonium bromide (TBAB) in mixtures of 2-propanol and water, and 3.0 m TPAB and 3.0 m TBAB in mixtures of 1-propanol and water. In addition, VLE measurements were made on 3.0 m TBAB in 2-propanol + water mixtures at 0.080 bar. The effects of the salt on the VLE in each system were assessed via relative volatilities. The effect of the solute was to salt-out at high alcohol concentrations and salt-in at low alcohol concentrations. A vibrating tube densimeter was used to obtain solution densities at 25 degrees C from 0.1 to 4 m TBAB or TPAB in the pure solvent and in aqueous 1-propanol and 2-propanol solutions. Variations of the apparent molar volumes with salt molality in the mixed solvent differed markedly from those of the alcohol-free binary, while subtle distinctions were seen among the various salt and alcohol molecular structures.