In the 1970s and 1980s, the Main Computer Center (MCC) of the State Planning Committee (Gosplan) of the USSR was one of the largest civilian computer centers in the USSR and in Eastern Europe. Available historical literature contains only the basic facts about this center. In this article, the history of the Main Computer Center of the State Planning Committee of the USSR is supplemented and refined. The article describes the prerequisites for its creation, the transformation of its structure, the chronology of the use of various computers for economic calculations. The author reveals new facts about the Main Computer Center, its leading role in conducting economic calculations on computers, and its coordinating role in organizing the work of the computer centers of the planning committees of the union republics and other socialist countries. This work is based on the works of Soviet computer scientists and historians, on official materials, on the personal memories and archive of the author (who worked as a programmer in the Main Computer Center of the USSR State Planning Committee in the 1970s) and on the memories and personal archives of his former colleagues.