Low pressure isobaric T-x-y data were determined for methyl benzoate-methyl p-toluate, methyl benzoate-dimethyl terephthalate and methyl p-toluate-dimethyl terephthalate systems at 6.6 and 13.3 kPa, as well as for some methyl benzoate-methyl p-toluate-dimethyl terephthalate ternary mixtures at 6.6 kPa. Both vapour pressures of two pure components and P-x isotherms for all three binaries at 433.15 K were also measured. The ebulliometer-type equilibrium still with manostat and an additional thermostat was used in all measurements. Liquid and vapour compositions were determined by g.l.c. Experimental equilibrium data were fitted to Redlich-Kister, Wilson, NRTL and UNIQUAC equations. Some predictions with UNIFAC method were also made.