A person familiar with his plans says Rep. John Dingell of Michigan, the longest-serving congressman in U.S. history, will announce his retirement on Monday.
The 87-year-old Dingell was first elected in 1955, filling the House seat vacated by his late father. The person was not authorized to speak publicly ahead of Dingell's announcement.
He became the longest-serving member of Congress last year.
Dingell is the former chairman of the powerful House Energy and Commerce Committee and the Democrat has been a master of legislative deal-making and staunch advocate for the U.S. auto industry.
Dingell has played a role in a number of major pieces of legislation, including President Barack Obama's health care overhaul, Medicare.
His plans were first reported by The Detroit News and The Detroit Free Press.