Thin films of CuGaSe2have been produced by rf sputtering. Compositional, structural, electrical, and optical properties are strongly influenced by growth temperature. At substrate temperatures lower than 300 °C amorphous or poorly crystalline Se‐excess films are obtained, showing high resistivity (≊103&OHgr; cm) and optical transitions at 1.62, 1.80, and 2.4 eV (values lower than the single‐crystal counterparts). At the higher growth temperatures, polycrystalline films are obtained (average grain size 0.7 &mgr;m) with lower values of resistivity (1 &OHgr; cm), and optical transitions at 1.68, 1.90, and 2.55 eV (very close to the single‐crystal values). A hopping conduction mechanism has been detected at the lower measuring temperature (T<150 K), and a grain boundary limited conduction process at the higher measurements temperature (T>150 K). Structural and compositional characteristics are used to explain the behavior observed in the electrical and optical properties.