A light emitting diode (LED) includes an LED chip, a casting, two metallic electrodes and a heat sink. The casting includes a first surface, a second surface and an outer peripheral side surface interconnecting the first and second surfaces. The casting defines a receiving space concaved inwardly from the first surface for receiving the LED chip therein. A through hole is defined in the casting and extends from the receiving space to the second surface. The metallic electrodes are separated from each other. Each metallic electrode includes a first terminal electrically connecting with the LED chip, and a second terminal disposed at the outer peripheral side surface of the casting. The heat sink is filled in the through hole and thermally contacts the LED chip. The heat sink is thermally and electrically insulated from the metallic electrodes by the casting.