In 1945 immediately after the end of World War II, the hospital was established as the 43rd Filed Hospital, an army tent set up by the 37th Infantry which came from Pangasinan under Major Anderson of the United States Marine Corps with cooperation with doctor Venancio del Rosario.

[2] The American-aided clinic later ceased operations but the defunct Philippine Civilian Auxiliary Unit was converted into Tuguegarao Hospital on June 25, 1945, by Gregorio M. Reyes, the first Cagayan chief and a doctor.

The wages and salaries of the Tuguegarao Hospital's staff and personnel were then funded through donations, shows and dance benefits.

[2] Teogenes Alfonso took over the hospital management on September 28, 1947, when Reyes resigned on the same year to open his own private clinic.

Justiniano M. Mendoza succeeded Alfonso who launched an intensive campaign targeted to people in rural areas to patronize the hospital's services and facilities.

A bill was proposed to change its name to Cagayan Valley Regional Hospital but did not prosper due to the EDSA Revolution of 1986.