The object of the present paper is to present the results of laboratory investigations of the clay composition of Samanid wares and discarded kiln items found in situ, in an effort to answer some of the questions raised by previous studies. Neutron activation analysis has been used to determine elemental composition patterns of wares collected from Afrasiyab and Nishapur. These have been compared with the clay compositions of kiln items from Nishapur and with sherds collected at a number of other sites in Kharasan and Transoxiana.