The main objective of the paper is to highlight the changes in the situation of the Hungarian minority in Romania and the Romanian minority in Hungary living in the divided Transylvania from the Second Vienna Arbitration from 30 August 1940 to the end of WWII. The author analyses the Hungarian and Romanian governments’ attitude regarding the new borders and their intentions with the minorities remaining on their territories. The paper offers a synthesis of the system of reciprocity, which determined the relations between the two states on the minority issue until 1944. Finally, the negative influence of the politics of reciprocity is shown on the interethnic relations in Transylvania.