Thin films were prepared, from C60 powders by vacuum evaporation and rf-plasma excited ion plating methods. The film structures ranged from fcc-polycrystal C60film to amorphous C60 film and to amorphous carbon films containing varying amounts of C60 molecules depending on the preparation method and conditions. Electrical conductivity of these films was found so sensitive to air that highly reproducible data were obtained only when the measurement was done by in-situ high vacuum conditions. The Co films deposited at 120°C on fused silica substrates by vacuum evaporation were amorphous and they had conductivities three orders of magnitude lower than those of fcc-polycrystal C60 films deposited on cleaved NaCl(100) substrates under the same conditions. The conductivities of both amorphous and fcc-polycrystal C60 films decreased drastically when these films were exposed to air. Partially decomposed C60 ion-plating films showed conductivities close to those of the air-exposed amorphous and fcc-polycrystal C60 films.