A liquid crystal display (LCD) device includes a data converter for processing first and second data signals, a backlight unit emitting light having a luminance, and a liquid crystal panel supplied with the light. The LCD panel has a first and second region corresponding to the first and second data signals. The data converter differently processes gray levels of the first and second data signals a and the luminance is adjusted when the first and second regions have different brightness. The LCD driving method allows presentation of different image regions on a screen, such as moving image screens and static image screens without brightness degradation.