This paper presents research conducted into cement production with an extremely low clinker content. Hoang Thach Portland clinker was used at a dosage of less than 10% by mass. Fly ash and ground granulated blast furnace slag (GGBFS) were utilized in varying proportion, with slag content ranging from 60 to 90% and fly ash content from 10 to 30%. The results show that all samples exhibited acceptable consistency and setting times. More importantly, the cement containing 90% GGBFS, 9.6% clinker and 0.4% gypsum demonstrated good compressive strength. Its compressive strength, at 28 days of age, exceeded 30 MPa, equivalent to 60% of that of conventional cement containing 96% clinker. Another mix comprising 80% GGBFS and 10% fly ash achieved a compressive strength of nearly 28 MPa, which represented 54% of the control sample’s strength. In conclusion, it is feasible to produce cement with ultra-low clinker content using ground granulated blast furnace slag and fly ash.