Cadmium selenide nano-crystallites are grown onto amorphous glass substrate from an aqueous alkaline medium, using chemical bath deposition method at room temperature. The samples are annealed in air for 4 h at various temperatures and characterized by structural, optical and electrical properties. The as-deposited CdSe layers grew in the nanocrystalline cubic phase, with optical band gap, 'E-g' 2.3 eV and electrical resistivity of the order of 10(6) Omega cm. After annealing metastable nanocrystalline cubic phase transformed into stable polycrystalline hexagonal phase. Depending upon temperature, decease upto 0.6 eV and 10(3) Omega cm were observed in the E-g, and electrical resistivity, respectively. These changes have been attributed to the increase in the grain size of the CdSe crystallites. (C) 2003 Elsevier B.V. All rights reserved.