An LCD device adapted to improve its picture quality in spite of the brightness variation includes: a gray scale modulator modulating R, G, and B data; a backlight dimming controller generating a back dimming signal that is inversely proportional to the modulated R, G, and B data generated in the gray scale modulator; and an over driving controller selectively overshoot-compensating the R, G, and B data from the gray scale modulator in every gray scale level through the comparison of the R, G, and B data of current frame and the R, G, and B data of previous frame, wherein, the modulated R, G, and B data each include maximum gray scale levels lower than those of the overshoot compensated R, G, and B data.