 He was a doctor for the Royal House, and for plenty of well-known people from the social life in Spain, but above it all he was a "beneficence doctor" (or of attention to the poorest people) at the Hospital Provincial de Madrid, nowadays called Hospital General Universitario Gregorio Marañón, where in 1911 was appointed at his own request in the unit of infectious diseases.Along with this hospital, the biggest one in Madrid, nowadays his name stands in the front of several streets and education institutions all over Spain.The Gregorio Marañón Foundation was established on 11 November 1988, with the aim of "perpetuate the thinking and work of Doctor Marañón, spread the high magistrature of Medicine he worked in and promote research in the fields of Medicine and Bioethics".