Being eligible for a breast reduction depends on where you live, according to plastic surgeons in West Sussex.
About 3,700 breast reduction operations are carried out each year
The medics from the Queen Victoria Hospital in East Grinstead surveyed 303 primary care trusts.
They found many trusts considered the surgery to be a cosmetic procedure and of low clinical priority and would refuse or limit funding for it.
The surgeons said the variation between trusts was "at odds with the ethos of the NHS".
Of the 80% of trusts which responded to the survey, 76% accepted that physical discomfort such as breast, back or neck pain was an indication for surgery although 10% of those said they would not normally fund it.
The research stated that bilateral breast reduction surgery (BBR) had well documented physical and psychological benefits with about 3,700 operations carried out in England each year.
But it found the criteria for surgery ranged widely between the trusts and led to a postcode lottery.
Some 12% of trusts required that a professionally fitted bra had not relieved symptoms before allowing the procedure, while 20% required women have a minimum cup size, ranging from DD to F.
Another criteria was based on body mass index, (BMI) with 90% putting it as a requirement.
The BMI requirement from trust to trust ranged from 25 to 32, meaning in one part of England a woman of 14st would be eligible but elsewhere she would only be allowed the operation if she weighed 11st.
The research said: "The large variation in criteria between trusts is potentially unfair and at odds with the ethos of the NHS."
The findings are to be presented at the National Meeting of the British Association of Plastic Reconstructive and Aesthetic Surgeons in London on Friday.