The Nanocrystalline thin films of CdS were successfully deposited by chemical bath deposition method. A blue shift is observed in the spectra comparing to that of the bulk CdS. The band gap measured for ethylenediamine was found to be in the range of 2.7-3.2 eV and for ethylenediamine tetra acetic acid was in the range of 3.4-3.8 eV.