The Research Institute in Mathematics and Physics (IRMP) of UCLouvain was created in 2009 following a reorganization of the university structures, according to which faculties would be responsible for teaching and research institutes for research. The IRMP is one of the 7 research institutes of the Science and Technology Sector of the university. The IRMP counts about 150 members from all over the world, including permanent scientific personnel (~30), postdoctoral researchers (~40), PhD students (~50), technical personnel (~25), administrative personnel (7), and scientific visitors (~25).

The IRMP develops research in Fundamental Physics and Pure Mathematics.

In Mathematics, research targets analysis, algebra, category theory, geometry, topology, mathematical physics, probability and mathematical education.

In Physics, research concerns fundamental interactions, statistical physics, cosmology, associated technologies and spin-offs.

In addition to research groups active in the domains mentioned above, the IRMP hosts the Cyclotron Resources Center (CRC) technological platform and various technical workshops and laboratories, often co-managed with other SST institutes, notably a mechanical workshop, an electronics laboratory, and a drawing office. The IRMP also contributes very significantly to the Center for High Performance Computing and Mass Storage (CISM), which is a technological platform shared at the entire university level.

The IRMP is proud of the scientific heritage of UCLouvain scientists like Georges Lemaître, cosmologist and recognized father of the Big Bang theory, and Charles de la Vallée Poussin, one of the greatest Belgian mathematicians. The Georges Lemaître chair and the Charles de la Vallée Poussin Chair are organized every year by the IRMP to honor these two scientists.