Bubble point pressure and dielectric spectra of propane+ethanol liquid mixtures were measured at 303.2 K. The bubble point pressure was measured by use of a static type apparatus. The experimental pressure increased with increase in the mole fraction of propane, and the tendencies were well correlated with NRTL equations. The dielectric constants decreased with the mole fraction of propane. Otherwise the dielectric relaxation times showed convex shapes for the mole fraction of propane. The excess dielectric constants and the excess inverse dielectric relaxation times showed negative values over the whole range of the propane concentration. These phenomena suggested that hydrophobic interactions and dipole dipole interactions play important roles in determining the dielectric properties of propane+ethanol liquid mixtures at the experimental temperature and pressure.