Problems related to archaeological culture and ethnos comparison in the case of medieval Bulgaria are discussed in the article. According to the author, in recent years it has become evident that the traditional concept and methodology of the study of the Bulgars’ ethnogenesis and ethnic history are in contradiction with the facts accumulated. The methods of “archaeological ethno-genetics”, which dictated solving problems of ethnogenesis of the ancient population belonging to an archaeological culture in direct correlation with ethnicity, are currently being criticized. According to modern ideas about ethnos and ethnicity, ethnicity is based upon identity with a complex hierarchical nature. Contemporary methodology requires proceeding with the integrated study of the problems of ethnogenesis on the basis of archaeology and ethnology. This kind of analysis is based upon the study of the medieval Bulgar mentality as a source of information on key aspects of ethno-political ideas. The analysis of authentic historical sources, historiographical tradition elements and folklore materials makes it possible to reconstruct the basic ideas that were significant for an ethnic group. The archaeological culture of the population of Bulgaria is characterized by two clearly distinguished and interconnected elements – the common Muslim culture and that of the elite military “druzhina” (squad). These elements directly characterize the Bulgar ethno-political community. These theoretical conclusions and empirical research concerning the case of the medieval Bulgars’ ethnogenesis attest to the productivity of ethnological synthesis techniques on an interdisciplinary basis.