The extensive investigation of the annealing effect in nitrogen atmosphere on the structural optical and electrical properties of chemically deposited CdS films on SnO2 has been performed. The as-deposited film shows 2.45 eV band gap (E-g) and decreases with increasing annealing temperature. The film annealed at 623 K having pure hexagonal phase (a = 4.14 angstrom, c = 6.71 angstrom for [1 0 0] plane) and E-g = 2.36 eV shows 10 times higher conductivity for all temperature range, and shows two different activation energies E-a = 0.114 eV and E-a = 0.033 eV for the temperature range 395 K <= T <= 515 K and 515 K <= T <= 585 K, respectively. The structural parameters such as dislocation density, strain and optical parameters such as absorption and extinction coefficient are calculated and compared for all the films. (C) 2010 Elsevier B.V. All rights reserved.