He has been trying to reach a suitable agreement about the future of DEI with his mother and DEI president Theresa Earnhardt.
"After a year of intense negotiation, we decided its time for us to move on and seek other opportunities for 2008," Earnhardt Jr. said at news conference. "We both want to get to the same place, but we have different visions on how to get there. At 32 years of age, the same age my father was when he made his final and most important career decision, it's time for me to compete on a consistent basis."
Earnhardt does not know which team he will drive for next season.
He is 12th in the latest Nextel Cup standings, and likely will be courted by many Nextel powerhouses, including Hendrick Motorsports, Joe Gibbs Racing, and Evernham Motorsports.
He has 17 Nextel titles.