The studies conducted by Ye.P. Kazakov in the archaeology of the Volga Bulgaria and the preceding period in the history of the region are considered in the article. The excavations of the Bulgar settlements and burial grounds (including the Bolshiye Tarkhany, Tankeevka, Tetyushi, Turaevo, Rozdestveno, II Komintern sites) have modified the views regarding the time and character of the Bulgars appearance in the Volga region and made it possible for Ye.P. Kazakov to create a new concept of the history of the Middle Volga and the Kama regions. Ye.P. Kazakov was the first to develop the chronology and periodization of the 8-10^th-century Bulgar antiquities and revised the chronologies and interpretations of the archaeological resources preceding the period of the Bulgars emergence in the Volga area. He singled out a separate pagan period in the history of the Bulgars, which, in his opinion, had completed in the late 10^th century. A number of components of differing origins within the culture of the Volga Bulgars were revealed by him. The Ugric (Magyar) one is considered most significant by the researcher. In order to study the peculiarities of the Volga Bulgaria economy and culture, Ye.P. Kazakov has systematized the vast material obtained by him in the course of the studies of the 10–13^th-century rural trade settlements on the Kama River.