What is now known as the University of Montemorelos traces its origins to the establishment in 1942 of the Mexican Industrial Agricultural School (EIAM) on the grounds of a farm known as "La Carlota" in the municipality of Montemorelos, Nuevo León, Mexico. Although the school offered mainly primary and secondary education with teaching of agricultural techniques, it also emphasized health care and attention. Thus, on August 6, 1946, the construction of the Montemorelos Hospital and Sanatorium began with funds donated by the then constitutional governor of the State of Nuevo León, the Honorable Arturo B. De la Garza, who bought the land and donated it to the Association Civil Philanthropic and Educational (ACFE). The Adventist Hospital and Sanitarium of Glendale, California donated $ 72,750.00 and the Kellogg Foundation $ 145,000.00. ACFE took care of all the other expenses through the Seventh-day Adventist Church. Collected donations from thousands of anonymous donors contributed significantly to the completion of the project.

The hospital was inaugurated on January 26, 1947. However, as its operations began, the need for well-trained nursing personnel became evident. This need led the leaders of ACFE, sponsor of the hospital, to establish a school of nursing which opened its doors on February 16, 1948. The nursing school which was affiliated with the Autonomous University of Nuevo León operated under the direct supervision of the hospital in the first twenty years of its existence. In 1950, EIAM changed its name to Montemorelos Vocational and Professional College (COVOPROM), an institution that in 1967 took control of the nursing program. In 1973 the Executive Power of the State of Nuevo León, granted the official recognition of University of Montemorelos (UM) to COVOPROM. All the careers and intermediate level studies offered became curricular options for the recently created institution of higher education.  One of the careers that was born with the newly formed university was the career of medicine. This resolution of the state executive was published in the Official Gazette on Saturday, May 5, 1973. Two years passed until 1975, when the UM School of Medicine received its first group of 41 medical students from which 28 graduated in the first class in June of 1979. 

On July 5, 1978, the World Health Organization added UM School of Medicine to the World Directory of Schools and Faculties of Medicine official publication after receiving confirmation from the Mexican government that the school was fully recognized. Therefore, since the fifth edition of this Directory published in 1979 until the most recent one, UM School of Medicine has always been included. On December 14, 1983, the Mexican Association of Faculties and Schools of Medicine (AMFEM) reported the unrestricted acceptance of the UM School of Medicine into the membership of that association after having been visited and evaluated. The opinion of AMFEM was given on December 9, 1983 by the Assembly meeting in the city of Matamoros, Tamaulipas. As a member of AMFEM, the School of Medicine automatically became a member of the Pan American Federation of Associations of Faculties (Schools) of Medicine (FEPAFEM) based in the City of Caracas, Venezuela.  

Throughout its 45 years of existence, 10 doctors have directed the school: Adelio Rocco (73–75), Kepler Hernández (75–82), Ricardo Chávez (82–86), Jochen Hawlitschek (86–90), Alejandro Gil (90–91, 93–97, 2000) Naif Cano (91–93), Francisco López (97–00), Nahúm García (2001–2012), Jorge Luis Salazar Guzmán (2013–2017) and Christian Moisés Aguilar Ríos (2017–present). 

So far, the School of Medicine has graduated  1,581 young people coming from 51 countries including:  Antigua and Barbuda, Argentina, Armenia, Bahamas, Barbados, Belgium, Belize, Bolivia , Brazil, Cameroon, Canada, Chile, Colombia, Costa Rica, Cuba, Curaçao, Ecuador, El Salvador, United States, Philippines, France, Guatemala, Guyana, Haiti, Holland, Honduras, India, England, Israel, Jamaica, Japan, Liberia, Martinique, Mexico, Nicaragua, Norway, Panama, Paraguay, Peru, Puerto Rico, Dominican Republic, Rwanda, Romania, Sri Lanka, Sudan, Thailand, Tanzania, Trinidad and Tobago and Venezuela.