The Chemical Bath Deposition Method (CBD) was employed for deposition of Cd1-xZnxS (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) thin films. The chemically deposited Cd1-xZnxS thin films were characterized by using UV-Visible spectrophotometer. Transmission spectra show the blue shifting of absorption edge as the Zn content increased. The x = 0.8 composition shows maximum 78 % transmittance. The reflection in the blue portion of the incident spectrum was decreased as the Zn content increased. The (αhν)2 versus photon energy (hν) curves shows tuning of band gap with Zn content. The observed band gap was 3.9 eV in the x = 0.8 composition. The effect of composition on refractive index, absorption index and other optical dispersion parameters were also investigated. The calculated values of average excitation energy Eo approximately obey the empirical relation (Eo=1.2 Eg) obtained from single oscillator model.