Sky has covered the NFL for a decade, including the Super Bowl, which this year was won by the Pittsburgh Steelers. The new deal covers the UK and Ireland and will run from the 2007/2008 season until the end of the 2010/2011 season.
Sky will more than double the number of live games it shows each season to 100, including all 10 play-off games in January.
In addition, it will extend its NFL coverage to include interactive TV, broadband and mobile.
Vic Wakeling, Sky's managing director of sport, said: "Viewers can look forward to more live games, a regular choice of simultaneous games and more NFL support shows."
The NFL is currently engaged in negotiations for terrestrial TV coverage over the same period as the Sky deal.
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