A method of manufacturing an image sensor is provided. In this method, a photoelectric conversion unit may be formed within a semiconductor substrate, wherein the semiconductor substrate includes an active pixel region and an optical black region. An annealing layer may be formed on the active pixel region and the optical black region and etched so that the annealing layer covers at least a portion of the optical black region. A wiring pattern may be formed on the annealing layer. A light-blocking pattern may be formed on the wiring pattern so as to cover the entire photoelectric conversion unit of the optical black region, thereby blocking light from being incident upon the optical black region.