In an LCD backlight unit using a light emitting diode, a double-sided printed circuit board includes a plurality of divided areas and conductive vias. A plurality of light emitting diodes are disposed on a top surface of the double-sided printed circuit board. A plurality of driving circuit connectors are disposed at a portion of the double-sided printed circuit board. A plurality of first lead patterns are formed on the top surface of the printed circuit board, each of the first lead patterns electrically connecting the light emitting diodes in each of the divided areas with one another. Also, a plurality of second lead patterns are formed on an underside surface of the double-sided printed circuit board to electrically connect the first lead patterns with the connectors through the conductive vias.