An LED lamp includes a housing, a holder and an LED device pivotally connected with the holder. The LED device includes a cylinder-shaped casing having opposite first and second openings and air venting holes near the first opening. An LED module and a heat dissipating fan are respectively mounted at two ends of a heat sink. The LED module, the heat sink and the heat dissipating fan are assembled together as a unit, which is received in the casing. An airflow generated by the heat dissipating fan is directed into the casing through the second opening. A portion of the airflow is exhausted out of the casing through fins of the heat sink and the first opening, and another portion of the airflow is exhausted out of the casing through the fins and the air venting holes of the casing.