The solubility of propylene in aqueous silver nitrate was measured by the pressure-drop method at temperatures from 278 to 308 K, at total gas pressures up to 0.64 MPa, and at silver nitrate concentrations from 1.0 to 6.0 M. From the temperature dependence of the solubility, values were determined for enthalpy and entropy changes. Solubility increased significantly with small decreases in temperature. The solubility of propylene increases with increases in pressure and silver nitrate concentration. The enthalpy and entropy of solution were found to increase with silver nitrate concentrations from 1.0 to 6.0 M; at 1.0 M AgNO3 the enthalpy was -23.5 kJ.mol(-1) and the entropy was -68.2 J.mol(-1).K-l; at 6.0 M AgNO3 the enthalpy was -25.8 kJ.mol(-1) and the entropy was -71.2 J.mol(-1).K-1. The propylene solubility in aqueous silver nitrate was empirically correlated as a function of system pressure (P), temperature (T), and silver nitrate concentration (c), and the correlation fits the results with an average error of +/-8%.