Dingell, 82, has served Detroit's western suburbs since December 1955 when he won the seat held by his father who died in office, The Washington Post reported.
Dingell, who has served a total of 19,420 days, was holding the gavel in 1965 when the House passed legislation creating Medicare. He also helped write the 1973 Endangered Species Act and led dozens of investigations into waste and abuse in federal agencies.
Dingell was known for pointing to a satellite picture of Earth and saying it illustrated the jurisdiction of the House Committee on Energy and Commerce that he was the ranking party member or chairman for almost three decades.
House Democrats dumped him from the post after the election last fall.
"One day you're up; one day you're down," Dingell said during an interview with the Post. "I'll be up again, don't worry."
Whitten served from 1941-95.
Notable deaths of 2014 [PHOTOS]