Aimed at helping in the post war rehabilitation of the country, the Rosario Institute opened its doors to the graduates of elementary schools of Rosario and nearby towns in 1946. Only first year classes were offered then, with an initial enrollment of 51 students.
Since its foundation, the Rosario Institute has continuously given unstinted support to the campaigns of the Philippine National Red Cross, BSP, GSP and other humanitarian agencies.
The problem of accommodation caused by the steadily increasing enrollment was remedied with construction of a two-room annex building. With improved revenues and resources, plans were made to construct own building in a new site. This was realized during the school year 1953-1954.
Rosario Institute has fully grown with the change of time and with the ever-changing needs of the society. The progress has been remarkable, and this can be attributed to diligent and conscientious management and supervision, competent teaching and non-teaching staff and the support of parents who have continually entrusted Rosario Institute of the delicate task of molding their children, intellectually and morally.
Now, after many remarkable years of existence, the Rosario Institute, situated on a one-half hectare lot along C. Abueg Street, has a two-storey main building or the Joshua Gabriel Tan Tinitigan Hall (JGTT Hall), two canteens, an Industrial Arts Building with TLE classroom, a covered court, a sepak takraw area, a badminton area and separate comfort rooms for boys and girls. The JGTT Hall houses ten (10) classrooms, a spacious library, Science and Computer laboratories, a bookstore, faculty room, and the Administrative offices.
Aside from that is the newly built Placido Panahon Tinitigan Hall or PPT Hall that houses classrooms, Office of the Vice Principal (Elementary) and school clinic.
Dedicated to the growth and development of both intellectual and moral, of the individual student, the Rosario Institute pursues its program of upgrading the competencies of its teaching staff. Needless to say, steps are taken mail brides towards strengthening decent character among students and teachers. Concerted efforts are fused to be relevant and responsive to the changing demands and needs of society.
To date, the school exists as a testimony of success along the lines of academic achievements plus an effective curriculum program with a long list of academic achievers and we are proud to say that the trust reposed in us has not been breached as we continue to produce quality graduates to follow the footsteps of thousands of our successful alumni in different fields: business, medicine, public service, justice, priesthood, engineering, accountancy and others—these are no mean feat!