Family doctors in Leeds are at the forefront of government reforms which have been described as tossing a "grenade" into the NHS.
A total of 82 GP surgeries across the city have put themselves forward to "dry run" Health Secretary Andrew Lansley's radical plans.
They will be among the first practices to be handed huge multi-million pound budgets and given the responsibility for planning and buying local health services.
The Leeds surgeries, which collectively care for more than 660,000 patients, were announced as "pathfinders".
One Parliamentary committee member considering the plans – Dr Sarah Wollaston, a GP – said it felt like "someone had tossed a grenade" into the NHS.
Under the reforms, groups of GPs will take over the 80bn budget of the country's 152 Primary Care Trusts and spend it on commissioning care for patients in their area.
The reforms will be rolled out across the country from April 2013.
The Leeds groups, which together cover around 75 per cent of patients in the city, are:
* The H3Plus Commissioning Group, which is made up of 31 practices in the city, covering 289,000 patients. It is chaired by Dr Gordon Sinclair, of Burton Croft Surgery in Headingley;
* Leodis Healthcare, comprising 28 surgeries with a combined patient list of 211,000 people;
* Calibre, comprising 23 practises and 178,000 patients.
NHS Leeds Chief Executive John Lawlor said: "We are delighted that the GP consortia in Leeds have been accepted onto the pathfinder programme and will be working together on the transition towards full implementation of the new commissioning arrangements.
"Throughout 2011/12, the consortia will start to take on increasing responsibilities for commissioning, using powers and budgets that will be delegated to them within the current statutory framework. They will also test the different elements involved in GP-led commissioning.
"This work in 2011/12 will provide the foundations for a final transitional year in 2012/13 during which consortia are established. They will then take on the leading responsibility for commissioning healthcare services," he said.