Дослідження присвячене змісту робіт та позиції буковинського історика Іона Янку Ністора, в творчій діяльності якого існували кілька періодів, з яких виділяється початковий, коли історик займався виключно історією середньовічної Молдавії. Міжвоєнний період, як і період Другої світової війни став часом поєднання досліджень з історії середньовічної з дослідженнями сучасності, що пояснюється участю професора у політичному житті країни як члена Націонал- ліберальної партії (1923-1938) та міністра у ряді урядів Румунії. У роботах представлено погляд на історію Буковини, здійснений з позиції державника, який захищав інтереси румунської держави. Це викликало і викликає заперечення з боку українських істориків. Ця відмінність змушувала І. Ністора на сторінках ряду своїх робіт полемізувати з сучасними йому українськими та радянськими істориками. Фактично наукова діяльність І. Ністора була досить активною і в 1940-х роках, хоча в цей час він звертав увагу як на теми політичного змісту, так і теми давньої історії румунів. Abstract. Ion Iancu Nistor is one of the well-known Bukovynians for his scientific, political and state activities, in relation to whom there are two opposite opinions in the Romanian and Ukrainian historical science. A native of Bukovyna, born into a peasant family, he was able to become a famous scientist. Studied at Chernivtsi and Vienna universities, had internships at the universities of Munich, Bucharest, Berlin. In 1912 he headed the Department of History of Southeast Europe Chernivtsi university. The sphere of interest in this period was the medieval history of Moldova. During World War I, Ion Nistor and his family lived in Romania, where he had been engaged in research activities for some time, and he became involved in political activities since 1917. The latter one made it possible, together with a number of refugees from Bukovyna, to join the Romanian National Council and take part in the preparation and conduct of the General Congress of Bukovyna, which paved the path for the first position in the Council of Ministers – the Minister of Bukovyna. In 1920, I. Nistor became the first rector of the Romanized Chernivtsi University and held this post for the second time in 1933-1940. Starting his creative activity with publications in «Junimea literară», the historian left great legacy in various directions. If in the initial period of his scientific activity I. Nistor touched upon the issues of the history of Moldova in the Middle Ages, in particular the issue of the country’s territorial borders, its relations with the Polish-Lithuanian Commonwealth, trade relationsof Moldova, then over time the range of scientific interests had expanded. In fact, the work «Romanians and Ruthenians of Bukovyna: a Historical and Statistical Study» (1915) was one of the first studies of the historian with political relevance. The issue of confrontation between Romanians and Ukrainians in terms of recognition of autochthony in Bukovyna was reflected in a number of other works. The work «Transnistrian Romanians» (1924) was a response to the intentions of the Soviet leadership to seek the return of Bessarabia under their rule, and the work «Czechoslovaks and Romanians» (1930) reflected the allied relations of the two states. The heritage of the historian also included works dedicated to the issue of the Great Unification, demonstrating the position on the issue of Bukovyna affiliation. The Ukrainian issue, one way or another, had always been present in a number of works during the interwar period, and it was important for the historian in the context of the attitude towards it from the USSR, Poland and Germany. In fact, the historian considered it his task to provide a historical background that was supposed to prove the right of the Romanians for entire Bukovyna. This was also manifested in his response to the statements of the Bukovynian OUN organization in June 1941, published in 1942. In addition to the issues mentioned, I. Nistor touched upon the issues of historical biography, the history of the Daco-Roman population, the history of Moldova in modern times, acting in line with traditional Romanian historiography.