Vapor-liquid equilibrium (VLE) data for the binary system of trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) + isobutane (2-methylpropane, R600a) were measured using a recirculation apparatus with view windows at four temperatures [(258.150, 268.150, 278.150, and 288.150) K]. The measured uncertainties of the temperature, pressure, and compositions are +/- 5 mK, +/- 0.0005 MPa, and +/- 0.005, respectively. All of the experimental data were correlated with the Peng-Robinson (PR) EoS using the Huron-Vidal (HV) mixing rule involving the nonrandom two-liquid (NRTL) activity coefficient model. The maximum average absolute relative deviation of pressure is 0.32 %, while the maximum average absolute deviation of vapor phase mole fraction is 0.0029. Azeotropic behavior can be found at the measured temperature range.