The "Simion Stoilow" Institute of Mathematics of the Romanian Academy is a research institute in Bucharest, Romania.
On December 29th, 1945, a group of twenty Romanian mathematicians from various institutions in Bucharest led by Dimitrie Pompeiu held a meeting at the University of Bucharest to establish The Institute of Mathematical Sciences with the aim of "promoting scientific research in mathematical sciences, through communications, talks, publications, congresses, and other means proper to this aim". In January 1946 they have registered the Institute as a legal person, specifically an NGO, with the Ilfov County Court. On June 9th, 1948 the new Communist regime revamped the Romanian Academy to an institution modeled on the Academy of Sciences of the USSR, increasing by 1966 the number of its member research centers and institutes from 7 to 56. Among the newly created institutes was The Institute of Mathematics of the Romanian Academy, established in 1949 on the basis of the previous NGO with the contribution of Simion Stoilow, one of the twenty founding members in 1945.
In 1974, Zoia Ceauşescu, a graduate of the Faculty of Mathematics of the University of Bucharest, and the daughter of Nicolae Ceauşescu, the communist head of state, was hired by the institute. Her parents were not happy with her choice in studying Mathematics. Provoked by a verbal disagreement with Miron Nicolescu, in April 1975, Ceauşescu issued a decree to close down the Institute. The ensued disruption of normal scientific life led to eventual departure from Romania of a number of leading mathematicians, including Ciprian Foias and Dan-Virgil Voiculescu. In 1978, with contribution from Zoia Ceauşescu some of the former members of the Institute were hired into a newly established Mathematical section of the National Institute Scientific and Technical Creation (Institutul National pentru Creatie Stiintifica si Tehnica, INCREST), previously known as the Institute of Fluid Mechanics and Aerospace Research (Institutul de Mecanica Fluidelor si Cercetari Aerospatiale, IMFCA), currently a private company (INAV S.A.), owned by .