An image sensor includes a photoelectric converter in a pixel area of a substrate to generate photoelectrons in response to an incident light that is incident onto the pixel area, a signal generator on a first surface of the substrate in the pixel area to generate electric signals corresponding to image information of an object in accordance with the photoelectrons, and a pixel separation pattern penetrating through the substrate from the first surface of the substrate to a second surface of the substrate opposite to the first surface of the substrate, the pixel separation pattern including an insulation pattern having a refractive index smaller than that of the substrate and a metallic conductive pattern enclosed by the insulation pattern, and the pixel area being enclosed by the pixel separation pattern and isolated from a neighboring pixel area.