An exemplary LED lamp includes a heat sink, and an LED module mounted on the heat sink. The heat sink includes a base, a receiving tube extending upwardly from a first face of the base, and a plurality of fins extending outwardly from an outer circumference of the receiving tube. The LED module is mounted a second face of the base. A plurality of through tunnels are defined in the base. The through tunnels extend through the base from the first face to the second face of the base. Each through tunnel communicates with an air passage between two neighboring fins.