Exoemissive properties of several CVD diamond films (undoped or doped with nitrogen) are studied by the thermally stimulated exoelectronic emission (TSEE) method. Some experimental results are obtained after UV or X-ray irradiation. After UV irradiation, a single TSEE peak is observed at 605 or 625 K, depending upon the growth parameters. The existence of the exoemission signal is related to the surface morphology: facetted surfaces give rise to exoelectronic emission, more especially in the presence of both 111 and 100 faces, while smooth surfaces do not or only to a limit extent. A possible indication of negative electron affinity is observed at about 273 K.