An image sensor includes a semiconductor substrate including a plurality of pixel regions, a first surface, and a second surface opposing the first surface, a plurality of transistors adjacent to the first surface of the semiconductor substrate in each of the plurality of pixel regions, a microlens on the second surface of the semiconductor substrate, and a plurality of conductive patterns in contact with the semiconductor substrate and closer to the second surface of the semiconductor substrate than to the first surface of the semiconductor substrate in each of the plurality of pixel regions.