The FA has been looking for a sponsor for the world's most famous cup competition for some time and E.ON will also sponsor the FA Women's Cup and the FA Youth Cup.
FA chief executive Brian Barwick feels the new deal will benefit football at all levels.
"The FA currently invests around £70 million a year into football right down to the grassroots," he said. "Income from our new sponsorship programme will further contribute to the promotion and development of the game at all levels."
It will not be the first time the FA Cup has had a sponsor, although until 1994 it had gone without corporate backing.
Littlewoods struck a deal that year which expired in 1998, and they were followed by AXA for the next four years.
However, the competition has been without a lead sponsor since, with five companies - Umbro, Nationwide, Carlsberg, McDonald's and Pepsi - appointed as 'FA Partners' from 2002 until July 31 this year.
Clubs will notice a positive impact of the new deal, which will serve to increase prize-money, itself a relatively new development.
The FA introduced round-by-round incentives for the 2001-02 season, and Barwick believes the move has been a success.
