To develop comprehensive models for multicomponent natural gas mixtures, it is necessary to have binary interaction parameters for each of the pairs of constituent fluids that form the mixture. The determination of accurate mixture interaction parameters depends on reliably collected experimental data. In this work, we have carried out an experimental campaign to measure the bubble point pressures of mixtures of n-propane and n-decane, a mixture that has been thus far poorly studied with only four existing data sets. The experimental measurements of bubble-point states span a composition range (in n-propane mole fraction) from 0.148 to 0.731, and the bubble-point pressures are measured in the temperature range from 270 to 370 K. These data, in conjunction with data from a previous publication on mixtures of n-butane + n-octane and n-butane + n-nonane, are used to determine binary interaction parameters. The newly obtained binary interaction parameters for the mixture of n-propane and n-decane represent the experimental bubble-point pressures given here to within 8% (coverage factor, k=2), as opposed to previous deviations up to 19%.