Coated calcium phosphate nanoparticles were prepared for cell transfection. A calcium phosphate nanoparticle served as core which was then coated with DNA for colloidal stabilisation. The efficiency of transfection could be considerably increased by adding another layer of calcium phosphate on the surface, thereby incorporating DNA into the particle and preventing its degradation within the cell by lysosomes. A subsequent outermost layer of DNA on the calcium phosphate gave a colloidal stabilisation. The efficiency of such multi-shell particles was significantly higher than that of simple DNA-coated calcium phosphate nanoparticles. The transfection efficiency of EGFP-encoding DNA was tested with different cell lines (T-HUVEC, HeLa, and LTK). The dispersions were stable and could be used for transfection after 2 weeks of storage at 4 degrees C without loss of efficiency.