Penistone and Stocksbridge MP Angela Smith defected to join the group in February – claiming she'd been left bemused and bewildered by Labour's stance on Brexit and anti-semitism.
But after Change UK's dismal showing in the European elections, Mrs Smith is one of six MPs to quit and become an Independent.
Ms Smith joins Hedi Allen, Chuka Umunna, Gavin Shuker, Sarah Wollaston and Luciana Berger in ditching the party after it secured just 3.4 per cent of the vote in the EU elections.
A joint statement from the six outgoing members said: “We are all immensely proud of the team of Change UK candidates and supporters who stepped forward to join us in making the unequivocal case for Remain in the recent EU elections.
“We believe Change UK boosted the campaign and the turnout.”
“To all the newly elected MEPs who stood on an unambiguous manifesto to remain, we offer our congratulations and support as we continue fighting togther for the UK to remain in the European Union.”
The MPS also thanked everyone for their support over the past four months.
The statement also said: “We believe that our priority now must be to provide collegiate leadership to bring people together in the national interest.
"We know the landscape will continue to shift within the political environment and have concluded that by returning to sit as independents, we will be best placed to work cross-party and respond flexibly.
"We wish our colleagues well as they continue to build Change UK."
Within hours of quitting Labour, Ms Smith was forced to apologise for sparking a racism row by saying in a live TV interview ‘it’s not just about being black or a funny tinge’.
"I was very tired at that point, having been on the go since 7am with no break whatsoever. I misspoke very badly. I’m very sorry for what I said, which is really not what I am, " she said.