CdSe quantum dots (QDs) were prepared by using a simple green route with CdSO4 and Na2SeSO3 in aqueous solution. Post synthesis hydrothermalmodification of CdSe QDs was performed to enhance the optical properties. The as prepared and the hydrothermally treated thioglycolic acidcapped CdSe quantumdots were characterized byUltravioletÂvisible (UVÂ vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Results demonstrated that CdSe QDs synthesized in aqueous solution showed a zincblende structure and a homogeneous size distribution with a mean particle size of about ranging from2.1 to 2.7 nm. The hydrothermal treatment slightly increases the QDs sizes and enhance the quantum yield (QY).