Silicate-based bioactive glasses undergo incomplete conversion to a calcium phosphate material after in vivo implantation, which severely limits their biomedical application. In this communication, novel borate-based glasses with controllable degradation behavior were developed and their bioactive potential was investigated in vitro. When immersed in a 0.02M K2HPO4 solution at 37 degrees C, these glasses reacted to form a carbonate-substituted hydroxyapatite (c-HA) on their surfaces, indicating their bioactive potential. The conversion rate to c-HA was controlled by adjusting the B2O3/SiO2 ratio in the glass composition. The results indicate the potential application of the borate-based bioactive glass as scaffold materials for bone tissue engineering.