We measured changes in the categorical color appearance of the peripheral visual field as a function of stimulus size. Simulated OSA color chips of 8 chromatic colors produced by an LCD projector were presented at the fovea (0 deg) and at several eccentricities in the temporal visual field. A large gray surround field was illuminated by D₆₅ fluorescent lamps at 2000 lx. The observer reported the color appearance of the stimulus with one of the eleven basic color terms. The results indicated that when the stimulus size increased to 10 deg diameter, it was possible for most of categories to achieve the same response at eccentricity of 90 deg. We derived sizes which had the same response with 50% consistency as the category obtained at the fovea. It is suggested that categorical color perception is constant across the whole visual field if the stimulus is sufficiently large.