The present invention provides a backlight unit and liquid crystal display device having the same, by which cooling performance is prevented from being lowered in a manner of arranging inverter elements in a horizontal direction. The present invention includes a lamp unit comprising a plurality of light-emitting lamps wherein electrodes are provided to both ends of each of the light-emitting lamps and an inverter provided to a rear side of the lamp unit in a horizontal direction to apply power to a plurality of the light-emitting lamps. And, the inverter includes at least one inverter printed circuit board arranged on a lower part of the rear side of the lamp unit in the horizontal direction and a plurality of transformers and inverter elements arranged on the at least one inverter printed circuit board in the horizontal direction.