Interest in diamond-like carbon (DLC) thin films has increased considerably in the last few years. It is suggested that DLC films may be used for electronic devices, especially working at high temperatures. The subject of this contribution is the electrical conduction of a metal/DLC/ Si system. The investigated DLC films were prepared by two methods: radio-frequency plasma chemical vapour deposition (RF-PCVD) and pulsed cathodic-arc discharge (PCAD) on silicon substrates. The metal/DLC/silicon heterojunctions show rectifying characteristics. The rectifying character of the current-voltage behaviour may be caused by a thin interfacial SiO2 sublayer existing between the DLC film and silicon.