Abstract: The relationship between Northern Hemisphere storm tracks at 300 hPa and the ENSO cycle, and the energetics of the storm tracks in winter seasons have been analyzed using ECMWF data. It is shown that during the El Ni?o events, the local Hadley circulation over the eastern Pacific is strengthened, and the Pacific jet extends equator ward and eastward, which causes the Pacific storm track to extend equator ward and eastward, while the La Nina events mark the opposite shifts. In the Atlantic region, during the El Ni?o events, the maximum wind of the Atlantic westerly jet decreases as the jet extends westward and equator ward, correspondingly, the Atlantic storm track also extends westward and equator ward, and weakens. The reverse is true for the La Nina events. The energy budget analysis shows that the baroclinic conversions are positive over the storm tracks and their upstream regions. During the El Ni?o events, the positive center of baroclinic conversion over the Pacific extends downstream and equator ward, whereas the positive center over the Atlantic extends westward and equator ward, which are in agreement with the shifts of the Pacific and Atlantic storm tracks. The baroclinic conversion due to the planetary-scale eddies is smaller than that due to the synoptic-scale eddies, and the baroclinic conversion due to the interaction of planetary-scale and synoptic-scale eddies is the smallest. It is also shown that the positive barotropic conversion centers are located upstream of the storm tracks while the negative centers are located in the storm track regions. During the El Ni?o events, the Pacific negative barotropic conversion center shifts poleward, the North American positive center shifts southward, and the Atlantic negative center weakens and becomes smaller. These are in agreement with the changes of the Pacific and Atlantic storm tracks. The barotropic conversion due to the synoptic-scale eddies is larger than that due to the planetary-scale eddies, and the contribution from the interaction between the planetary-scale and synoptic-scale eddies is very small.