In order to make spintronics practically viable, it is important to explore magnetic semiconductors which are ferromagnetic at or above room temperature. There have been many reports on RTFM particularly of wide-gap semiconductors doped with 3d transition-metal ions. Zn chalcogenides are important host materials which are known to support RTFM. ZnSe and ZnTe doped with Mn, Fe, Co, Ni and Cr have been investigated. ZnS with a wide band gap (3.68 eV) has a great potential for device applications and has been identified as an excellent host semiconductor for supporting RTFM when doped with a variety of 3d transition metal ions such as Mn, Co, Cu and Fe. Surprisingly, inspite of both applied and academic interests, Cr-doped ZnS in nano form has been least studied. In fact as per literature, there are only a few reports on structural and optical properties of Cr-doped ZnS, and no reports on magnetic studies. In view of these factors, Cr has been chosen as the dopant for the present investigation.