A printed circuit board (PCB) includes a base substrate, an electrical wiring, a dummy pad and a thermally conductive adhesion member. The base substrate includes a light-emitting diode (LED) mounted on a first surface of the base substrate. The electrical wiring is electrically connected to the LED. The dummy pad is formed on the first surface to be connected to the electrical wiring. The thermally conductive adhesion member is attached to a second surface of the base substrate. Therefore, superior heat radiation may be obtained, thereby reducing or preventing damage to the LED and the LCD device using the LED by radiating the heat from the LED used as a light source.