The potential energy surface of a model propane dimer was systematically mapped with quantum chemical calculations. The calculations included approximately 12 separation distances between the monomers for each of 121 different relative geometries, or 1487 different configurations. The generated potential energy map reveals that the most attractive interactions are those having a maximum number of close contacts between carbon and hydrogen. The potential well depth of the most attractive orientation found was -1.625 kcal mol(-1). The complete ab initio energy surface was fitted to a simple model consisting of pairwise-additive interatomic potentials, each modeled with a modified Morse function of interatomic distance. The resultant model accurately represents the entire propane dimer ab initio energy surface. The efficacy of the generated parameter set was tested with previously published ethane dimer energies and propane routes not included in fitting. The new parameter set is consistent with these results indicating a high level of transferability for the interatomic C-H, C-C, and H-H potentials obtained.