Metal‐carbon‐metal structures were fabricated using either gold or aluminum evaporated electrodes and rf plasma (methane) deposited ‘‘diamondlike’’ carbon films. ac‐conductance and capacitance versus voltage and frequency (10 Hz to 13 MHz) data were taken to determine the dielectric properties of these films. Conductance versus frequency data fit a generalized power law, consistent with both dc and hopping conduction components. The capacitance versus frequency data are well matched to the conductance versus frequency data, as predicted by a Kramers‐Kronig analysis. The dielectric loss tangent is nearly constant at 0.5 to 1.0% over the frequency range from 1 to 100 kHz. The dc resistivity is above 1013&OHgr; cm, and the dc breakdown strength is above 8×106V/cm in properly prepared samples.