An automatic white balance control image apparatus, medium, and method. The automatic white balance control imaging apparatus may include a color space conversion unit converting the input image data into color space data having a chromatic component, a gray region extraction unit extracting a gray region for the input image data based on gray regions for light sources, the gray regions being detected based on plural light sources and a predetermined color checker, a detection unit extracting initial light source information using a color gamut average value and a color gamut center value, and adjusting the initial light source information in order for a chromatic component introduced into the extracted gray region to be excluded, a gain control unit calculating gains to scale the input image data based on the adjusted initial light source information, and controlling a white balance by applying the calculated gains to the input image data.