Surrey Downs CCG surveyed all GPs - including salaried and locum doctors - across its 33 practices about plans to downgrade A&E and maternity care.
More than 74% of GPs opposed plans to downgrade Epsom Hospital, which is part of Epsom and St Helier University Hospitals NHS Trust.
The proposals were put forward under the Better Services Better Value (BSBV) programme, made up of several CCGs and hospital trusts proposing to reconfigure care across south-west London and Surrey.
Surrey Downs CCG chairwoman Dr Claire Fuller said: 'As a GP-led commissioning group, we are charged with securing the best health outcomes for our population and we must do so within the resources we are allocated.'
But she added that the 'important ballot result' showed local GPs did not think the BSBV programme met local patients' needs.
'This decision is not taken lightly or without due care and consideration of patients and colleagues in south-west London, but our responsibility has to be to our local patients.
'We are not ruling out service changes in the future, but we will now withdraw from the BSBV programme and with our partners, focus our work on achieving the improvements we want to see locally.'
CCG chief officer Miles Freeman said: 'Our next steps are to make our vision for out-of-hospital care a reality, so patients benefit from having integrated care delivered more effectively and efficiently.
'This important ambition can only be achieved with the support of patients and families, our partners in both health and local authorities, and I now look forward to discussing our plans more widely.'