Visible and near infrared cathodoluminescence of Bi2Sr2CaCu2Ox and YBa2Cu3O7−x films is investigated in the scanning electron microscope. In particular, possible analogies in the cathodoluminescence of both systems have been analyzed. The spectra show only minor and slightly defined common features. Low-temperature observations show the capability of the cathodoluminescence technique to detect fine structural transitions. Some transformations induced by the electron beam are described.