The Grade School Department occupies a wing of the whole structure which was built in 1966. It has its own facilities like the library, two IMC rooms, Science Laboratory, H.E. Room, Guidance Office, two Computer Room, HELE Room, Music Room, and Medical Clinic. Some facilities are shared with the other departments.
In the beginning, San Sebastian College-Recoletos catered to boys exclusively. Later, in 1973, due to numerous requests abetted partly by neighbor schools that phased out their grade school, the department opened its environment to girls. Since then, SSC has become co-educational.