Calcium phosphate (CaP)/block copolymer hybrid porous nanospheres were synthesized by a simple solution method using CaCl(2) and (NH(4))(2)HPO(4) in the presence of a block copolymer at room temperature. X-ray diffraction showed that the sample consisted of amorphous calcium phosphate (ACP). The BET specific surface area and the pore size distribution of the CaP/PLLA-mPEG hybrid porous nanospheres were also characterized. The as-prepared CaP/PLLA-mPEG hybrid porous nanospheres were explored as drug carriers, and showed a high ibuprofen loading capacity and in vitro prolonged drug release behavior in a simulated body fluid. These CaP/block copolymer hybrid porous nanospheres exhibit a great potential for application in drug delivery. (C) 2010 Elsevier B.V. All rights reserved.