Luminescent lanthanide doped SiO2/Hydroxylapatite (HAp) core/shell nanoparticles (NPs) were synthesized by sol-gel technology. The resulting NPs exhibited an amorphous SiO2 core and a crystalline luminescent shell. The formation of the HAp layer was possible at pH 8.5. The characterization of the resulting NPs was done by transmission electron microscopy, X-ray diffraction analysis, inductively-coupled plasma combined with optical emission spectrometry, and photoluminescence spectroscopy. Additionally, the newly developed SiO2/HAp:Ln3+ core/shell NPs were tested for their biocompatibility, e. g. by an in vitro cell culture based assay.