A facile room-temperature method for the fabrication of calcium phosphate (CaP)/PLGA-mPEG hybrid porous nanospheres has been developed. The hybrid CaP/PLGA-mPEG nanospheres obtained were 20∼60 nm in diameter and exhibited porous structure, and they were applied as DNA vectors for DNA loading and in vitro transfection. The results showed that the DNA binding capacity and transfection efficiency of the as-prepared hybrid porous nanospheres were much higher than those of the CaP precipitates prepared according to the standard CaP transfection procedure and mesoporous silica reported before. MTT assays confirmed that the CaP/PLGA-mPEG hybrid porous nanospheres were quite safe. In addition, both CaP and PLGA-mPEG are biocompatible and biodegradable, thus the as-prepared CaP/PLGA-mPEG hybrid porous nanospheres are promising in gene delivery.