Facile synthesis of quantum dots(QDs)of ZnS without capping agent is reported.Cubic phase of ZnS is confirmed using both X-ray diffraction and high resolution transmission electron microscopy.Absorption studies using UV–vis spectroscopy reveal strong quantum confinement effect for a typical ZnS of 3 nm size with a band gap of4.46 eV in comparison to the bulk value of 3.55 eV.Photoluminescence study shows the presence of the surface defects.