The successful n-type doping of epitaxial diamond films grown on (111) oriented synthetic type Ib crystals is shown. Fourier Transform Infrared spectroscopy, cathodoluminescence, and Hall effect were employed to characterize a set of phosphorus-doped diamond films grown under similar conditions by CVD with different phosphine concentrations in the reactant gas ([P]/[C] = 250 to 500 ppm). The activation energy of the conductivity shows a good agreement with the value known for phosphorus-doped sample (about 0.6 eV). Infrared measurements show the characteristic absorption peaks related to neutral substitutional phosphorus. Hall effect measurements clearly indicate n-type conductivity with mobility equal to 40 cm2/Vs at room temperature and a phosphorus concentration in the film of about 1018 cm—3. Cathodoluminescence measurements showed the free excitons and bound exciton peaks related to phosphorus. Bound-exciton recombination without phonon emission was also observed.