A compact torsionally oscillating crystal viscometer was used to measure viscosity coefficients of propane.To derive viscosity coefficients,resonance frequencies and bandwidths of the crystal were automatically measured with a developed measuring system and its software.Viscosity data of propane were derived at temperatures ranging from 303 to 430 K at pressures up to 20 MPa in their liquid regions.The uncertainty of the measurements was estimated to be about 5%.The experimental data were compared with calculated data from a standard correlation.