A heat dissipation system is used for dissipating heat generated by an electronic device mounted on a printed circuit board. The heat dissipation system includes an enclosure adapted to receive the electronic device therein, the enclosure having a base plate on which the printed circuit board is mounted. A spreader adapted for contacting the electronic device in the enclosure. A plurality of fins disposed between the printed circuit board and the base plate, the fins thermally engaging with the base plate. A heat pipe is used to thermally connect the spreader and the fins together, which are positioned at opposite sides of the printed circuit board, respectively. Accordingly, the enclosure can help to dissipate the heat generated by the electronic device.