Along the Black Sea coast from Istanbul to Theodosia, USSR, and in some other places, such as Thessaloniki, a lot of typologically identical sgraffito ceramics have been excavated, their origin being unknown but mostly supposed to be Byzantine. Of special interest are the sgraffito ceramics decorated with monograms. Some of the monograms are attributed to the Palaeologi family others are unidentified but supposed to be Byzantine as well. Neutron activation analysis (NAA) has been used to determine 32 elements in 101 samples from sgraffito ceramics excavated in Shumen, Varna, and Tchreven, northeastern Bulgaria. The analytical data were subjected to cluster and stepwise discriminant analysis. The results proved that 75% of the analyzed samples are of local production including those decorated with monograms. It is difficult to conclude where the rest of the investigated pottery was made, but cluster analysis proves that there is at least one more place outside northeastern Bulgaria which supplied such ceramics to this region.