A linear-logarithmic image sensor includes a pixel array, a signal generation unit, and a control unit. The pixel array includes at least one unit pixel that generates a leakage signal corresponding to leakage photo-charges and that sequentially generates a first analog signal corresponding to a portion of accumulated photo-charges and a second analog signal corresponding to a whole of the accumulated photo-charges by resetting a floating diffusion node and transferring the accumulated photo-charges from a storage node to the floating diffusion node in response to first and second transfer control signals that are sequentially activated. The signal generation unit includes at least one signal generation block that generates a final analog signal based on the leakage signal, the first analog signal, and the second analog signal. The control unit controls the pixel array and the signal generation unit.