The origin of UNSJ was a Preparatory College founded in 1839 by then-governor (then president of Argentina) Domingo Faustino Sarmiento.

The faculty of Mineralogy of this college gave rise to the technical School of Mines, which in turn fathered other teaching institutions.

Also in that year, courses to form professors in Sciences and Letters began at the Sarmiento Normal School.

In 1968 a programme to create new state universities did not include San Juan, but renewed demands led to a feasibility study.

The National University of San Juan was created by Law 20367, signed by de facto President Alejandro Agustín Lanusse, on 10 May 1973.