The University of Milan was founded in 1924 from the merger of two institutions that boasted a great tradition of medical, scientific and humanistic studies: the Accademia Scientifico-Letteraria (Scientific-Literary Academy), active since 1861, and the Istituti Clinici di Perfezionamento (Clinical Specialisation Institutes), established in 1906. By 1928, the University already had the fourth-highest number of enrolled students in Italy, after Naples, Rome and Padua. Its premises are located in Città Studi (the City of Studies), the university district built from 1915 onwards (that is also home to the Politecnico), where scientific schools have its headquarters, and in several buildings in the historic city centre, which house the humanities schools.
At the time of its foundation, there were four "traditional" schools - Law, Humanities, Medicine and Mathematical, Physical and Natural Sciences; then, in the 1930s, the Schools of Veterinary Medicine and Agriculture were introduced, after the aggregation of the old schools of Veterinary Medicine (1792) and Agriculture (1871). At the end of the Second World War, the old Ospedale dei Poveri (Hospital for the Poor) building, known as "la Cà Granda" (the Big House), was assigned to the University. The building, one of the first Italian examples of civil architecture - commissioned in the 15th century by the Sforza family, the dukes of Milan - was seriously damaged by the bombings of 1943. In 1958, after a complex series of reconstruction and renovation works, it became home to the University Rector's Office, the administrative offices and the schools of Law and Humanities.
In the 1960s, due to the extension of compulsory school attendance and the subsequent liberalisation of access to higher education, the number of people entering Italian universities progressively increased and the University of Milan enrolled more than 60,000 students. The University added to its range of courses and at the same time increased its number of centres. Two new schools were established, Pharmacy and Social and Political Sciences, which were based, respectively, in Città Studi and in Via Conservatorio, in Milan city centre.
Città Studi was also the site of a new complex, intended entirely for the biology departments, which was the work of architect Vico Magistretti. There was also an increase in the number of agreements with the city's hospital facilities, where students from the School of Medicine receive their clinical training. In 1968, the University was occupying approximately 127,000 m2 (1,370,000 sq ft); by the beginning of the 1980s this had increased to 205,000 m2 (2,210,000 sq ft). In 1989 there were 22 degree courses and 75,000 enrolled students, which increased to 90,000 by 1993. In view of this increase, the University began a process of streamlining and delocalising its facilities: from 1986 onwards, new centres began to appear in other areas of Milan, particularly in the Bicocca district, as well as in other parts of the region: in Como, Varese, Crema and Lodi.
In 1998, the University split in two and the city's second public institution was founded: The University of Milan-Bicocca. The University of Insubria was also established in Varese, bringing together courses that were already offered at Varese and Como by the Universities of Milan and Pavia. At the conclusion of this process, notwithstanding the reduction in the number of students, the University of Milan was still the largest institution in Lombardy and still one of the largest in the country.
The 2001 law that transformed the education system opened a new phase of change. The University updated its range of courses, trying to adapt them to better suit the evolution of the social demand for education and the innovation of the production system: thus, the number of degree courses rose to 74 and there was a new increase in enrolments. There was also an increase in the University's commitment to providing student services (orientation, internships and training, online education) and in investments for new education and research facilities, covering approximately 80,000 m2 (860,000 sq ft).
The most recent phase of expansion concerned the fields of communication science, intercultural mediation and art, but there are also ongoing projects relating to the sectors of information technology, veterinary medicine and biomedicine. Furthermore, there was also a strengthening of commitment to technology transfer and the practical application of scientific research results in the economic-production context.