Provided is an image sensor and method for manufacturing the same. The image sensor includes a semiconductor substrate including a photodiode for each unit pixel, an interlayer insulating layer including metal lines on the semiconductor substrate, and an optical refractive part in a region of the interlayer insulating layer corresponding to the photodiode for focusing light on the photodiode. The optical refractive part can be formed by implanting impurities into the interlayer insulating layer.