The influence of cadmium salt and thiourea concentrations and deposition time on the optical and electrical properties of chemical bath deposited CdS thin films has been studied. The decrease in cadmium salt and increase in thiourea concentrations, to the order of 1 mM and 100 mM respectively, have been found to be optimal for raising the optical transmission without conductivity deterioration and allowing a suitable thickness control less dependent on the deposition time. Additionally, 200 and 400 degrees C air-annealing treatments for 20 min have been carried out. Their analysis has demonstrated the optical absorption edge shifts towards lower photon energies as the air-annealing temperature raises. Besides, dark and light resistivities decrease in comparison with as-grown CdS data.