A metal to insulator transition has been observed in praseodymium films during in situ hydrogen loading (p(H2) = 1.015 x 10(5) Pa) at temperatures greater than or equal to 323 K. The transition can be observed at room temperature, if praseodymium films an coated with Palladium dots before hydriding. The transition is accompanied by a change in optical appearance, i.e. metallic grey praseodymium films change to yellowish transparent praseodymium hydride films. Glancing angle X-ray diffraction (GAXRD) patterns have revealed the fee structure of the films with an average lattice parameter of 5.611 Angstrom. An indirect optical bandgap of 3.0 eV has been obtained for praseodymium hydride films from reflectance and transmittance data.