TGA- stabilized CdTe nanocrystals (NCs) were prepared using sodium tellurite as tellurium source, which avoids the cumbersome processes associated with H2Te or NaHTe sources. Fluorescent CdTe/SiO2 composites were prepared by a sol–gel method without the exchange of surface ligands. The composites were characterized with TEM and fluorescence spectrophotometer and investigated their stability in phosphate-buffered saline (PBS) buffer. CdTe NCs were loaded into the core of silica spheres during the formation of composite spheres. In contrast to CdTe NCs in aqueous solutions, CdTe NCs in the composite revealed better stability and the luminescence peak show red-shift.