Abstract: The invention concerns a method for measuring the thickness of very thin, electrically conducting films of the order of 1 to 1000 nanometers and measuring apparatus for performing the method. The thickness of the electrically conducting films is measured by means of high-frequency electromagnetic waves in the microwave range by use of the surface resistance and consideration of the conductivity of the film as a measure of the film thickness. The thickness determination makes use of the reflection factor and/or the transmission factor of the microwave on the conductive film. This can be done with the aid of two antennas in free space in the far field of these antenna arrangements or, if the antennas are designed as waveguide flanges, it can also be done in the near field, in which case the waveguide flanges are arranged opposite each other at a very small distance.