The changes in the structure of reactive pulsed laser-deposited (RPLD) CNx films with nitrogen content from 3.6-22 at% have been investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared (FT-IR) absorption. The films were found to be amorphous, and to consist of a network of rings. The rings that were composed solely of carbon atoms gave rise to an XPS peak located between 284.3 and 284.8 eV (C-1 component). The rings containing nitrogen led to another peak located between 285.5 and 286.4 eV (C-2 component). When the nitrogen content increased, the relative intensity of the C-1 component fell, while that of the C-2 component rose, indicating that some carbon atoms in the rings were replaced by nitrogen atoms. C=N bonds also contributed to the C-2 component. The FT-IR data were consistent with this interpretation. No evidence for the existence of a beta-C3N4 phase was found in RPLD CNx films.