A simple synthetic route called; seed mediated growth technique was used for preparing fluorescent/magnetic bi- functional CdTe nanoparticles. The fluorescent CdTe nanocrystals prepared in aqueous solution were used as seeds, and then magnetic materials (metal hydroxides) were deposited on them to obtain two functions in a material. Five different (core-shell) composite nanoparticles were prepared. The results show that the nanoparticles with a shell of metal hydroxides have good optical properties. The thermal analysis (TG/DTG curves) was recorded for the nanoparticles to confirm...