Electrical breakdown structures of metal-polymer-metal differing nature and thickness of the polymer films was studied in this paper. Structures with films of polymethylmethacrylate, polycarbonate and polystyrene have been investigated. It has been found that the duration of current pulses detected in the breakdown of the polymer film does not exceed 500 ns. Nature polymeric dielectric does not affect the shape and parameters recorded in the breakdown of the current pulses. Importance has a film thickness. In the breakdown of the polymer films thicker than 0.5 microns having electrical overvoltage of short duration. Their value is several times greater than the magnitude of the breakdown voltage.