Dr Stoate is MP for Dartford and a practising GP
Labour MP Howard Stoate has said he will quit at the next election because new second jobs rules mean he will no longer be able to practise as a GP.
He said he believed the change would "diminish" his work as an MP.
Among reforms brought in after the expenses scandal, MPs now have to register more details of second jobs.
Dartford MP Dr Stoate is one of 33 MPs to announce their intention to stand down at the next election, since the expenses stories began.
New rules requiring MPs to register more details of their earnings and time spent on second jobs came into force on 1 July.
But Conservative leader David Cameron has said all his party's frontbenchers will give up any outside jobs by December, to prepare for the general election.
Dr Stoate said he had been re-elected twice since 1997 by voters who knew he was a practising GP, but recent debates about second jobs had made him reconsider.
"It is apparent that Labour candidates standing for Parliament at the next election will be expected to give up their outside jobs if they are elected," he said.
"I respect this view but I think my own contribution to the work of Parliament would be diminished if I was to give up general practice, which is why I have decided not to stand as a candidate at the next general election."
More than half of MPs with outside interests are Conservatives but many have said they will give up their second jobs.
Among high earners are Michael Gove, the shadow schools secretary, who gets £5,000 a month for his columns in the Times, and David Willetts who is paid £60,000 a year as a pensions adviser.
Other MPs who have found their second jobs under the spotlight are Labour's Nick Raynsford, who reportedly received £148,000 from six private sector jobs last year and the Lib Dem MP John Hemming, who gets more than £200,000 a year from his software company.
Dr Stoate said he felt his experience as a GP had helped him in his work on the Commons health committee: "I have never allowed my medical responsibilities to interfere with my parliamentary duties and I have always been open and upfront with my constituents about my ongoing work as a GP."
His expenses details were highlighted in the Telegraph which reported he had claimed £55,836 in four years, for a flat 15 miles from his constituency home, on which he paid no rent or mortgage.
He said his claims had always been modest and his flat had been in an appalling condition when he bought it but he had done most of the repairs and refurbishments himself - many of the claims had been for DIY equipment.
He has repaid all claims under the second homes allowance for this year saying it had become "completely discredited".