Isothermal vapor-liquid equilibria for the binary mixtures of trifluoromethane (R-23) + 1,1-difluoroethane (HFC-152a) and trifluoromethane + 1,1,1-trifluoroethane (HFC-143a) were measured at 283.15 and 293.15 K. The experiments were carried out with a circulation-type equilibrium apparatus with the measurement of temperature, pressure, and the compositions of the liquid and vapor phases. The experimental data were correlated with the Peng-Robinson equation of state using the Wong and Sandler mixing rules and the Carnahan - Starling - Desantis (CSD) equation of state. Calculated results with these equations showed good agreement with the experimental data, but the Peng-Robinson equation of state gave more accurate predictions for the binary systems. Azeotropic behavior has not been found in either of these mixtures.