The solubility of potassium nitrate in aqueous 2-propanol solution has been determined at the temperatures of (298.15 and 313.15) K and atmospheric pressure. The densities, viscosities, refractive indices, and electrical conductivities of potassium nitrate in water and in the saturated solutions of aqueous 2-propanol were measured at these two temperatures. Solubilities were determined using the analytical gravimetric method. Densities were determined using a vibrating-tube densimeter. Viscosities were measured with an automatic microviscometer based on the rolling ball principle. Refractive indices were measured using a digital Abbe-type refractometer. Electrical conductivities were determined by measuring the electrical resistance between two electrodes facing each other in the solution. The experimental values of solubility, density, and electrical conductivity were found to decrease with an increase of the concentration of 2-propanol for the saturated of potassium nitrate + water + 2-propanol, while different trends with a maximum and a minimum were observed for viscosity and refractive index, respectively. Equations are given for these properties as a function of concentration.