Phosphorus-containing SBA-15 mesoporous materials have been tested as alendronate delivery systems. The incorporation of phosphorus into the silica network originates materials with enhanced alendronate loading capability and sustained release kinetics compared to pure silica SBA-15. The PO 4 units incorporated into the silica framework provide these carriers of greater affinity towards host drug molecules due to the presence of higher number of interaction sites. Furthermore, in vitro tests into a simulated body fluid demonstrate that P-containing SBA-15 materials are bioactive, since they develop an apatite-like layer onto their surfaces after 14days of assay. The synergic effect of alendronate release capability and subsequent bioactive behavior makes phosphorus-containing SBA-15 materials good candidates to be used as bone substitutes for the local treatment of bone diseases associated with bone resorption.