There is provided a backlight unit for an LCD device. The backlight unit, disposed under a liquid crystal panel and emitting light to a liquid crystal panel, includes a lightguide plate, a light emitting diode (LED) array disposed at an edge of the lightguide plate and including a plurality of LED blocks each including at least one LED emitting white light, and a controller controlling a current signal applied to each of the plurality of LED blocks to regulate the luminance of each LED block. Accordingly, the backlight unit can be provided, which is capable of contributing to manufacturing thinner and larger products and realizing effective local dimming by using an LED disposed at an edge of the lightguide plate.