An LED lamp includes a hollow first heat sink (10), a plurality of LED modules (40) respectively mounted on outer sidewalls (120) of the first heat sink, a second heat sink (20) being enclosed by the first heat sink, and a plurality of heat pipes (30) connecting the second heat sink to the first heat sink. The second heat sink includes an annular base (22) and a plurality of fins (24, 240) extending outwardly and radially from an outer sidewall of the base. The heat pipes couple the base of the second heat sink with the first heat sink, so that heat generated by the LED modules can be transferred from the first heat sink to the second heat sink via the heat pipes, thereby enhancing a heat dissipating efficiency of the LED lamp.