In the paper, the experimental data on the temperature effect on the breakdown strength of polypropylene, polycarbonate and poly(ethylene terephthalate) films 2.0–2.5 μm thick have been obtained over a temperature range from 293 to 363 K. When the film samples were heated, the breakdown electric field strength was found to decrease slightly but to reveal a significant scatter of values. It was shown that the experimental results on the pulsed electrical breakdown of the polymer films could be described basing the notion of the ionization mechanism of the polymer breakdown, not related to the development of an impact ionization of the polymer molecules.