The spectral characteristics of cometary nuclei are poorly known. To help rectify this situation, we have been obtaining spectra of cometary nuclei when they are favorably located, i.e., sufficiently far from the Sun that little cometary activity remains. In this work we present moderate resolution (10- (\AA) Full Width at Half Maximum) CCD spectra of five comets at large heliocentric distances (Chiron, P/Arend-Rigaux, P/Giacobini-Zinner, P/Tempel 2, and (P /) Encke) and five cometary nucleus candidates ([5145) Pholus, 3552 (1983 SA), 944 Hidalgo, 3200 Phaethon, and 2212 Hephaistos]. Any near-nucleus coma contamination was carefully subtracted using the spatial information along the spectrograph slit and the resulting spectra are believed to represent the nuclei themselves. Our results show that cometary nuclei are spectrally diverse, with a range that is greater than hitherto suspected, from slightly blue (reflectivity gradient (S^{\prime}=-3 % / 10^{3} \AA) ) to very red ( (S^{\prime}=20 % / 10^{3} \AA) ). A similar range of colors is shared by the cometary nucleus candidates. The new spectra are compared with previous spectra of cometary nuclei and cometary nucleus candidates. 01993 Academic Press. Inc.