This　paper　describes　a　successful　synthesis　of　water　soluble　CdTe(S)　nanocrystals　(NCs)　with　high　quantum　yields　(QYs)　via　a　mild　photochemical　route　in　one　step　with　thioglycolic　acid　as　the　stabilizer　and　sulfur　source.　The　precursor　solution　of　mixed　cadmium　chloride,　freshly　prepared　sodium　hydrogen　telluride　and　thioglycolic　acid　was　subjected　directly　to　UV　irradiation　using　a　500　W　high-pressure　mercury　lamp　under　the　protection　of　N-2.　NCs　with　a　small　particle　size　(2.2　nm)　and　a　high　photoluminescence　quantum　yield　(up　to　80%　at　room　temperature)　were　formed　within　25　min.　The　NCs　were　characterized　by　UV-vis　absorption　and　fluorescence　spectroscopy,　transmission　electron　microscopy,　powder　X-ray　diffraction　and　energy-dispersive　X-ray　spectroscopy　to　evaluate　their　structure,　size　and　composition.　The　photochemically　prepared　NCs　were　compared　with　CdTe　NCs　prepared　by　conventional　hydrothermal　synthesis　and　CdTe/CdS　core/shell　NCs　obtained　by　post-preparative　photochemical　passivation.　The　effects　of　UV　irradiation　intensity,　illumination　time,　temperature　and　concentration　of　Te2-　on　the　optical　properties　of　NCs　were　studied　in　detail.