Safe and efficient gene delivery would have great potential in gene therapy and tissue engineering, but synthetic biomaterial surfaces endowed with efficient gene-transferring functions do not yet exist. Inspired by naturally occurring biomineralization processes, we co-precipitated DNA with inorganic minerals onto cell-culture surfaces. The DNA/mineral nanocomposite surfaces obtained not only supported cell growth but also provided high concentrations of DNA in the immediate microenvironment of the cultured cells. Gene transfer from the engineered surfaces was as efficient as an optimized commercial lipid transfection reagent; in addition, the extent of gene transfer was adjustable by varying the mineral composition. DNA/mineral nanocomposite surfaces represent a promising system for enhancing gene transfer and controlling the extent of gene transfer for various biomedical applications, including tissue engineering or gene therapy of bone.