The study is devoted to the examination of the problem related to the involvement of party and state bodies in the study of ethno-national issues in the MSSR in the period 1944-1956. The materials invoked testify that the research in this field has been permanently under the watchful eye of the Communist Party, the organs of Soviet power and the KGB. The Soviet historical science was politically directed by party and state organs. After the reannexing of Bessarabia to the USSR in 1944, the Soviets made every effort to determine that the research of ethno-national issues in the scientific institutions of the MSSR, as well as in the Union scientific centers, would prove the thesis emitted in the interwar period, that the Moldovan population is a different people than the Romanian people and speak another language, the “Moldovan language”, different from the Romanian language. The numerous decisions of the party and state bodies invoked in this study, attest that this problem was permanently in the attention of the party, state, local and union bodies, their control and direct interference in the research process, that had determined not only the research topics, but also the main conclusions to be reached, such as the primacy of the Slavs living in these territories and the later arrival of the Romanian population, the great role of the Slavs/Eastern Slavs in the establishing of “Moldovan people”, different from the Romanian people, and “Moldovan language” distinguished from Romanian language