An image sensor is provided. The image sensor may include first to fourth unit pixels. The first unit pixel includes a first photodiode, a first transfer gate, and a first floating diffusion region, and the second unit pixel includes a second photodiode, a second transfer gate, and a second floating diffusion region, and the third unit pixel includes a third photodiode, a third transfer gate, and a third floating diffusion region, and the fourth unit pixel includes a fourth photodiode, a fourth transfer gate, and a fourth floating diffusion region. The first photodiode and the third photodiode may be N-type photodiodes. The second photodiode and the fourth photodiode may be P-type photodiodes.