The room‐temperature cathodoluminescence of diamondlike films produced by glow discharge is reported. The material was deposited onto dc biased substrates maintained at relatively low temperature (<100 °C). Two visible peaks around 2.3 eV (green) and 2.7 eV (blue‐violet) were identified which are commonly found in natural and synthetic diamond, indicating the presence of crystalline particles in the films. Moreover, x‐ray diffraction spectra of the samples before cathodoluminescence studies are identical to the ones reported for natural powder diamond.