Abstract Thermal conductivities of binary refrigerant mixtures (R125 + R152a), (R125 + R1234ze(E)), (R143a + R1234ze(E)), (R143a + R1234yf), (R1234ze(E) + R1234yf), (R125 + R1234yf), and (R134a + R1234ze(E)) were measured in the homogeneous liquid and vapour phases using the transient hot-wire technique. The measurements span temperatures from (260 to 414) K with pressures from (0.9 to 3.1) MPa. Two transient hot-wire sensors designed for measurements in the liquid and the vapour phase, respectively, were used and the relative uncertainty of both was estimated to be 1% or better for pure fluids. The performance of the sensor for the liquid phase was verified with water and toluene while argon was used to validate the sensor for the vapour phase. These measurements and previously published data were used to tune binary interaction parameters in the extended corresponding states model implemented in the NIST software REFPROP 9.1. Deviations between the tuned model and measured thermal conductivities were mostly within ± 3% which is consistent with the uncertainties of the reference equations of the pure fluids.