Ni-C composite films were prepared using a codeposition method, their structure and electrical properties were investigated. Depending on experimental conditions, two typical structures are found for as-deposited Ni-C films: i) amorphous Ni-C alloy film; ii) granular film with Ni3C granules and inter-granule amorphous carbon. The amorphous Ni-C films show ohmic conduction behaviour with very high resistivity. On the other hand, granular films with high carbon content show semiconductive characteristics. The electrical property and conduction behaviour are correlated with the film structure. Besides, the crystallization behaviour of the amorphous Ni-C film was also studied.