An electrochemical route for the generation of Te²⁻ ions in an aqueous solution, with high yield and great stability, was developed and applied for the preparation of CdTe quantum dots (QDs) stabilized by negatively or positively charged ligands. An aqueous Cd(ClO₄)₂ solution containing mercaptopropionic acid (MPA) or cysteamine (Cys) stabilizers was directly added to the electrochemically generated aqueous telluride ion solution. This one pot process is quite reproducible and clean (no chemical reducing agents), allowing control of reduced species generation. The CdTe QDs showed good stability and high luminescence with particle average sizes of d = 3.1 nm (MPA) or 2.7 nm (Cys). Macrophages were efficiently labeled with MPA-capped CdTe QDs as well as with Cys-capped CdTe QDs.