An apparatus and method for detecting flicker in a camera module is provided. The method including generating a first image frame and a second image frame, setting up a first sampling area in the first image frame and a second sampling area in the second image frame, sampling a plurality of horizontal lines from among all of the horizontal lines contained in each of the first sampling area and the second sampling area, accumulating brightness values of pixels located on each of the sampled horizontal lines to generate first accumulated brightness values for the first image frame and second accumulated brightness values for the second image frame, and detecting flicker based on the first accumulated values and the second accumulated values, wherein the first sampling area and the second sampling area have the same sizes and the same horizontal starting points but have different vertical starting points.