An image sensor includes a substrate and first and second transfer gates. The substrate includes not only a photodiode in which photocharges corresponding to the amount of incident light are accumulated, but also a floating diffusion (FD) region in which the photocharges are received and accumulated. The first and second transfer gates transmit the photocharges from the photodiode to the floating diffusion (FD) region. At least some parts of the first transfer gate are formed to overlap with the second transfer gate.