Nanocrystalline cadmium sulfide thin films were successfully grown on Si(100) substrates using microwave assisted chemical bath deposition technique. Aqueous solutions of cadmium chloride (CdCl2) and thiourea [SC(NH2)2] were used as cadmium Cd+2 and sulfur S-2 ions sources, respectively to prepare nanocrystalline CdS thin films. The effect of reagents molar concentration on the quality of the prepared CdS thin films was investigated. Analysis revealed that using the chemical bath deposition technique aided by microwave irradiation good quality nanocrystalline CdS thin films can be grown on Si substrates by relatively short deposition time. Simple and cost effective way was introduced to synthesis nanocrystalline CdS thin films on Si substrates that would have potential application prospects in optoelectronic applications.