Calcium-based bone cements are widely used in dental and orthopaedic surgery. Those based on calcium phosphate (CPCs) or calcium silicate (CSCs) have a number of favourable properties that encourage their clinical use in bone defect repair. The purpose of the present study was to compare the in vitro osteogenesis and bacteriostatic activity of BoneSource CPCs with home-made CSCs, particularly in regard to their facility for cell differentiation. Cement in vitro osteogenic activity was evaluated by incubating the cement specimens with human mesenchymal stem cells (hMSCs). The bacteriostatic activity of the two cements against Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacterial strains was assessed using a bacteriostasis ratio assay and by inhibition zone examination. Compared with CPC, CSC was shown to promote greater proliferation and osteogenic differentiation (alkaline phosphatase and osteocalcin), and the formation of mineralization nodules of hMSCs. It is worth noting that CSC could effectively induce hMSC differentiation, even when the culture medium did not contain osteogenetic differentiation agents. Compared with CPC, CSC also showed significantly greater bacteriostatic activity, as revealed by inhibition zones and the bacteriostasis ratio. Our findings suggest that CSC is a useful bioactive material for bone repair in terms of inducing cell differentiation, and may be considered an alternative to CPCs.