New experimental data on the thermal conductivity of propane are reported that allow improved correlations to be developed. Previous correlations have been limited by a lack of thermal-conductivity data for the vapor at temperatures below 300 K and liquid data near the critical point. In addition, significant discrepancies were noted in the high-temperature dilute-gas thermal conductivity. The present data cover the temperature range from the triple point at 85.5 K to 600 K and the pressure range 0.1 to 70 MPa. They are estimated to have an uncertainty of 1% for measurements removed from the critical point and at pressures above 1 MPa, which increases to 3% in the critical region and 4% at low pressures (<1 MPa). These new experimental data are used together with the previously available data to develop improved correlations for the thermal conductivity of propane. The thermal-conductivity correlation for propane is estimated to have an uncertainty of about 3% at a 95% confidence level, with the exception of state points near the critical point and the dilute gas, where the uncertainty of the correlation increases to 5%.