IMIM was created by the City Council of Barcelona in 1947, following the suggestion of the then Director of the Hamburg Tropeninstitut, Professor Nauck, to Dr. Trias de Bes, who was the Director of the then Hospital of Infectious Diseases which is today's Hospital del Mar. Thanks to the support of Dr. L. Garcia Tornel, who then was the Health Assistant to the Mayor, IMIM's creation became a reality. IMIM's activity started with an assignment to Dr. Trias for a presentation on slow progressing endocarditis at the 1947 Cardiology Congress in Barcelona.
Dr. Trias assigned the experimental portion of the presentation to Drs. J. Gras and A. Foz, whose work later became associated with the launch of the Research Institute.
In 1948 Sir Alexander Fleming innagurated the Tropical Medicine Pavilliona. In 1950, under the direction of Drs. Jordi Gras and Amadeo Foz work was initiated to transform the Pavillion into the Research Institute.