The primary objective of the present work is to make a comparison between the red glossy slip of Urartian pottery (commonly known as Urartian red polished ware) and local clays by conducting a variety of examinations. As a result of these investigations, the authors will suggest the most likely clay sources for ceramics and the slip that may have been used by the Urartian potters. Four samples from Ayanis Fortress have been characterised from the chemical, mineralogical, morphological and petrographic points of view. Scanning electron microscopy, optical microscope, X-ray diffraction, energy dispersive spectrometry, chemical analysis and colour measurement investigations have been carried out on the ceramic body and red glossy slip to determine their characteristics and technological features. In addition, three local clays were characterised by chemical, mineralogical and petrographic analyses. Test pieces made from local raw material were fired in a traditional updraft mud-brick kiln in order to better understand the paste and red-slip- making processes of Urartu. The results obtained from the different analyses demonstrate significant similarities between ceramic samples and fired clay test pieces. It may be concluded that it is possible these local clays were used in production of Urartian red glossy ceramics.