An apparatus for canceling a fixed pattern noise in a CMOS image sensor includes a storage device, a fixed pattern noise operation circuit, and a fixed pattern noise canceling circuit. The storage device stores first reference fixed pattern noises operated in a vertical blank section of an (n−1)th frame. The fixed pattern noise operation circuit calculates second reference fixed pattern noises based on the first reference fixed pattern noises stored in the storage device and blank fixed pattern noises output in a vertical blank section of an n-th frame and outputs the second reference fixed pattern noises to the storage device to update the first reference fixed pattern noises to the second reference fixed pattern noises. The fixed pattern noise canceling circuit cancels active fixed pattern noises in combination signals based on the combination signals output in an active section of an (n+1)th frame and including the active fixed pattern noises and pixel signals and the second reference fixed pattern noises output from the storage device.