In this research, bone-cements based on zinc modified tricalcium silicate (C3S, Ca3SiO5) are synthesized through solid-state reactions. Zinc oxide was added to replace part of CaO in order to stabilize the C3S phase. The 7.5 mole % ZnO added samples showed the least free CaO impurity; the ones added with 5 mole % ZnO revealed the best compressive strength that reaches 166 MPa (compared with those without ZnO 100 MPa). In vitro direct contact tests using primary cultured osteoblast persuaded of no observable cytotoxicity. These cements show remarkable self-setting properties and good strength hence are potential in bony and dental restorations.