David Marshall chaired Transport and Scottish Affairs select committees.
The government is facing another by-election after Glasgow East MP David Marshall announced he was stepping down on health grounds.
A Scottish Labour Party spokesperson said Mr Marshall had written to members to say his health had deteriorated.
The 67-year-old has a 13,507 majority and has been a Labour MP since 1979.
The news came as Scottish Labour leader Wendy Alexander resigned, and after Labour were pushed into fifth place in Thursday's by-election in Henley.
The Scottish Labour Party added: "David Marshall has indicated to local members in Glasgow that he will step down as a Member of Parliament.
"Our thoughts and prayers are with him at this time and we wish him a speedy recovery."
Labour's deputy leader Harriet Harman said: "He is a strong and committed supporter of the trade union movement in Scotland.
"A proud son of Scotland, he has fought at Westminster to improve the lives of the people in Glasgow East, the constituency that he has loved and served."
David Marshall has sat on the Labour benches since 1979, but has never held any frontbench positions.
He has chaired two select committees, Transport and Scottish Affairs.
He was strongly opposed to replacing Trident, campaigned for Celtic manager Jock Stein to be awarded a posthumous knighthood and in a memorable parliamentary speech denounced World Cup referees as "incompetent and short-sighted".
He is married with three children.