The deal means he will remain with the team his late father started. Terms were not released, but it is Earnhardt Jr.'s first one as a driver on the Winston Cup circuit.
Earnhardt Jr., who turns 29 on Friday, has been with the team his father started since 1998, the year he won the first of two straight NASCAR Busch Series championships.
Dale Earnhardt, Inc. is owned by Teresa Earnhardt, Dale Earnhardt's widow.
"Dale and I built this organization with a long-term plan in place," Teresa Earnhardt said. "Dale Jr. has always been an intricate part of that plan, and this agreement represents our commitment to one another and reaching the goal of winning championships."
Earnhardt Jr. finished third on Sept. 28 in the EA Sports 500, won by his DEI teammate Michael Waltrip.
Earnhardt Jr. is third in the points standings, 325 points behind leader Matt Kenseth.
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