This paper report the density, viscosity, thermal conductivity, and heat capacity of 10 samples of poly(methylsiloxane) liquids (molecular mass from 298 to 14 887) at atmospheric pressure over the temperature range from 293 K to 493 K. The maximum relative measurement error is +/0.05%, +/-2.4%, and +/-0.8% for density, viscosity, and heat capacity, respectively.