Proposals to bring together the primary care trusts (PCTs) of Great Yarmouth in Norfolk and Waveney in Suffolk have been approved by the government.
The plans are part of a major review of health which will see three strategic health authorities (SHA) in the region merged into one East of England SHA.
This will be formed from the old Beds and Herts, Essex, and Cambs, Norfolk and Suffolk SHAs.
The number of PCTs in the new SHA area will go from 41 to 14.
The new PCTs are: Norfolk PCT, Suffolk PCT, Cambridgeshire PCT, Peterborough PCT, and the Great Yarmouth and Waveney Teaching PCT.
Great Yarmouth MP Tony Wright, who spearheaded a Great Yarmouth and Waveney PCT merger campaign, said the decision was "overwhelmingly supported by the feelings of the community".
The new PCTs in the old Bedfordshire and Hertfordshire SHA are Bedfordshire, Luton Teaching, West Hertfordshire, and East and North Hertfordshire.
The new PCTs in Essex are West Essex, Mid Essex, North East Essex, South West Essex Teaching, South East Essex.
PCTs are responsible for a wide range of local health services, including GPs, hospitals and mental health services.
Keith Pearson, chair of the new East of England SHA, said: "There were compelling arguments for larger county based PCTs on the one hand and locality based PCTs such as Peterborough and Great Yarmouth and Waveney on the other.
"I look forward to working closely with the new organisations which will be formally established on 1 October 2006."
New PCTs being formed which are in the eastern region, but not under the East of England SHA, include: Northamptonshire Teaching, Buckinghamshire and Milton Keynes.