Due to the unprecedented increase of enrollment in San Pablo City National High School, it could no longer accommodate all the students coming from eight barangays of San Pablo. This problem was solved through the assistance of the city mayor, Hon. Vicente B. Amante & other local officials. Schools were brought by the local government to the barrios. Apprehended to this, through the Sanguniang Barangay of Stmo. Rosario headed by the late Chairman Elias Corales, the site, the owner of the land real-property was donated to the city Government pursuant to the Kapasyahan Blg. 93-3 dated July 1, 1993 citing the need for the construction of a barangay high school which can be effected through the support primarily of the city government. This school foundation & establishment started the first school construction of a three-classroom one storey building in a one hectare government lot.
Santisimo Rosario Annex together with the four annexes (1). Del Remedio Annex, (2). Dolores, (3). Santo Angel, & (4). Annex V started to operate in the school year 1995-1996 to unload the burden of parents concerning the transportation expenses.
SY 1995-1996, four pioneer teachers were assigned in Santisimo Rosario Annex. They were Mr. Ronie Nacario who was designated as Teacher-in-Charge, Mrs. Teresa Yema, Miss Maritess Fandiño and Miss Michelle D. Benedictos. The following year on January 1996, Mrs. Editha L. Fule became one of the initial teaching forces of Stmo. Rosario High School With Mr. Ricardo T. Manalo as principal of the City High main and its annexes.
The same year, June 1996 to be exact, a two-room building was constructed since enrollment increased due to an additional year level. Another building was raised the year after, it was donated by the Lions Club of San Pablo City, Progressively, as supported by the General Parents Teachers Association of the consecutive batches, Mr. Pruden Esturas as PTA President 1995-1999, Mr. Melvin Cuenca 2000-2002 and Ret. Col Roberto Cuasay 2003 to 2008, five more classrooms were added, computer laboratory was built in 2004 number of teachers were also increased from four to sixteen. The following are names of teachers according to dates they were in. Lorelie Caringal Mission, Renante M. Bonilla, Analyn N. Nacario, Rafaela M. Sarmiento, Noreen C. Aviñante, Gina C. Valencia, Perlita V. Delos Angeles, Annaliza Ampong, Gemma Mediana, Rubelyn N. Enero, Sarah J. Sario, Jun Pornobe who were once loaned from elementary department.
Unfortunately, due to the remoteness of the school and continuous increase of jeepney fare at that time, some teachers were voluntarily transferred to other schools near their homes. For that, another sets of teachers were assigned to the school, Nancy Sudario, Maritess Matuto, Jennefer Sesgundo Dimaranan, Rechel A. Rivera, Laila Hermosa Pere Godoy, Sherwin Belen, Krishen Labrado, Mercedes Prudenciamo, Imelda Mendoza, Laarni Zacarias, Rudy Gonzales, Benedict Rapsing & Liezel L. Katigbak.
Mr. Manalo as principal of the school city high main & its five annexes nurtured & guided the students & teachers in all academic & extra-curricular activities. All school affairs headed, from him downward to remote annexes, dissimilated through teachers-in-charge/ teacher leaders to teachers. Consequently, by this school annexes system, the Stmo. Rosario had the pride with its concrete proofs of excellence. The school became an agent of academic & sports excellence linking the barrio students to division, regional & even national competitions bringing home the prizes, medals, plaques & trophies. These are all exhibited at the school administrative office. On matters of school administration & education supervision, Mr. Manalo appointed subject area department heads for the annexes’ assistance. In Santisimo Rosario Annex, they were , Mrs. Aurora Cornelia (Science), & then Mrs. Helen Ramos (Science).
Santisimo Annex accredited to become national high school and become Santisimo Rosario National High School in 2005. Aqua-green uniform is implemented to replace white and green-checkered motif as a symbol of independence from San Pablo City National High School in 2006. On its first implementation of the new uniform, many others schools mistakenly identified rosarians as a private school students. Aqua-green and grey P.E uniforms for Rosarians was took effective in 2012. New buildings for SRNHS was build to accommodate more students in 2013 to 2014.
During the transition of education system of the Philippines from 10-year basic education system to K-12 system; Stmo. Rosario NHS is accredited to offer senior high school as a part of implementing K-12 curriculum in 2015, also this is the year where the last commencement exercises for old secondary curriculum occurred. New buildings for senior high school students was built in 2016.
In April 6, 2017, The first graduation of senior high was held Santisimo Rosario National High School is the first public high school in San Pablo City to produce senior high graduates.