Forty-eight sets of the saturated liquid densities and bubble-point pressures of the binary HFC 152a + HCFC 142b system were measured with a magnetic densimeter coupled with a variable-volume cell. The measurements obtained at four compositions, 20, 40, 60, and 80 wt%, of HFC 152a cover a range of temperatures from 280 to 400 K. The experimental uncertainties in temperature, pressure, density, and composition were estimated to be within ±15mK, ±20kPa, ±0.2%, and between −0.14 and ±0.01 wt% HFC 152a (−0.01 and + 0.14 wt% HCFC 142b), respectively. The purities of the samples were 99.9 wt% for HFC 152a and 99.8 wt% for HCFC 142b. A binary interaction parameter, k ij , in the Peng-Robinson equation of state was determined as a function of temperature for representing the bubble-point pressures. On the other hand, two constant binary-interaction parameters, k ij and l ij , were introduced into the mixing rule of the Hankinson-Brobst-Thomson equation for representing the saturated liquid densities.