Aluminum doped and undoped CdS films were prepared by chemical bath deposition technique and the photoelectrochemical (PEC) properties have been studied by forming doped CdS/NaOHNa 2SS/C junction. Better results are obtained with 0.1 wt% Al doped CdS films. These results are discussed with the help of the optical and transport properties of the Al doped CdS films.