Disclosed is an image sensor. The image sensor includes a semiconductor substrate including unit pixels, an interlayer dielectric layer including metal interconnections formed on the semiconductor substrate, a plurality of bottom electrodes formed on the interlayer dielectric layer in correspondence with the unit pixels, the plurality of bottom electrodes includes bottom electrodes having at least two different sizes, a photodiode formed on the interlayer dielectric layer including the bottom electrodes, and color filters formed on the photodiode in correspondence with the unit pixels.