Former minister Doug Touhig has announced he is to leave the Commons, the third senior Labour MP to announce his retirement in the past week.
Touhig has been the MP for the Welsh seat of Islwyn since 1995 and served as PPS to Gordon Brown before joining the whip's office in 1999.
He later served as a minister in the Welsh Office and the MoD.
"I have been active in politics for over 45 years and had the privilege of serving for 35 years - 15 years as MP for Islwyn and 20 years before that on Gwent County Council," Touhig said in a statement.
"After 35 years I think it is time to move on.
"I am associated with a number of voluntary organisations and I hope to continue this work.
"I owe a great debt to the Labour Party and the people of Islwyn who have placed their confidence in me to represent them in Parliament."
John McFall, the respected chairman of the Commons Treasury committee, said on Thursday that "having reached normal retirement age, I see this as a natural time to move on and explore other areas of interest".
He is expected to be offered a seat in the Lords. McFall has been the MP for West Dunbartonshire since 1987.
Last week a government minister announced he is to stand down from the Commons and said the stress of parliamentary and government business was responsible for the breakdown of his marriage.
Ian Pearson has been MP for Dudley South since 1994 and is the economic secretary to the Treasury.
"Since I have been a minister, I have been spending four or five nights a week in London," he said in a letter to party activists in his constituency.
"The pressure of working in London for such long periods put an enormous strain on my marriage.
"Sadly, we have grown apart because of the time I have been spending away on parliamentary and government business in London and Northern Ireland when I was a minister there."
Pearson has since divorced.
In his letter he said he wants to find "a better balance between my working and personal life".
So far 130 MPs have announced they are standing down - 83 from Labour, 35 Conservatives, seven Lib Dems, three independents (Clare Short, Andrew Pelling and Derek Conway), Alex Salmond from the SNP and Plaid's Adam Price.
ePolitix.com's ELECTION 2010 pages
