Compositions in vapor and liquid phases for the binary systems 1,1,1,2-tetrafluoroethane (HFC-134a) + m-cresol and HFC-134a + p-cresol were measured by a dual recirculation technique over a pressure range from (0.3 to 2.4) MPa at (343.2, 363.2, and 383.2) K. Vapor-liquid equilibrium was also measured over the same temperature and pressure ranges for the ternary system HFC-134a + m-cresol + p-cresol with three different ratios of m-cresol to p-cresol in the liquid phase.