Isothermal vapor-liquid equilibrium data of binary trifluoroiodomethane (R1311) + 1,1,2,2-tetrafluoroethane (R134) systems at 258.150, 263.150, 273.150 and 283.150K were measured by a recirculation apparatus with visual windows. The measured uncertainties of the temperature, pressure, and compositions are less than +/- 5 mK, +/- 0.0005 MPa, and +/- 0.005, respectively. All the experimental data were correlated by the Peng-Robinson (PR) EoS with the Huron-Vidal (HV) mixing rule utilizing the non-random two-liquid (NRTL) activity coefficient model. Azeotropic behavior can be found at the measured temperature range. (C) 2011 Elsevier B.V. All rights reserved.