Experimental (vapor + liquid) equilibrium data were obtained at sub-atmospheric pressures of (6.66, 13.33, 19.99, 26.66, 33.33, 39.99 and 46.66) kPa for the binary system (1,2-propanediol + 1,3-propanediol) over the entire composition range using Swietoslasky-type ebulliometer. Wilson and NRTL activity coefficient models were used to correlate the experimental VLE data for which optimum binary interaction energy parameters are reported. NRTL model fitted well with experimental data as compared to Wilson model. Density and refractive indices of binary mixtures are also reported along with their excess properties such as excess molar volumes (V-m(E)), excess refractive index (n(E)), partial molar volume ((V) over bar (i)), apparent molar volume (V-circle divide i), and excess partial molar volume ((V) over bar (E)(i)) at different temperatures (293.15 to 318.15) K. The excess molar volumes data were used to test the applicability of Prigogine-Flory-Patterson theory and refractive index values to test different mixing rules. (C) 2016 Elsevier Ltd. All rights reserved.