Doctors deny older people treatments they would offer younger patients, according to a study.
Researchers said the results showed doctors were ageist
Researchers writing in the Quality and Safety in Health Care journal said it demonstrated doctors in the NHS were guilty of ageism.
The University College London team questioned 90 GPs and consultants about the treatment of 72 patients aged 45 to 92 with angina problems.
They found nearly half of the doctors treated the over-65s differently.
Some 46% of GPs and elderly care doctors, known as gerontologists, and 48% of cardiologists acted in this way.
Overall, older patients were less likely to be prescribed a statin to lower their cholesterol, referred to a cardiologist, or given an angiogram or revascularisation - a procedure to open up the blood vessels.
However, they were significantly more likely to have their medication changed and told to come back at a later date.
The doctors said their reasons for treating patients differently were to do with the patients' wishes, potential complications and the frailty of the individual concerned.
One doctor said: "I think generally you have to try and identify from an individual what is in their best interests.
"I don't think bypass surgery in an 87-year-old is in their interests."
But lead researcher Professor Ann Bowling said: "We took into account factors such as the risk treatment presents elderly people, which may persuade doctors against treatment.
"And even with this, doctors were being influenced by the age of patients. It is ageism and should not happen.
"But I think it reflects our attitude to older people in society as a whole."
The results angered charities representing elderly people, as the government issued guidelines six years ago saying treatment decisions should not be based on age.
Dr Lorna Layward, research manager for Help the Aged, said: "It is shocking that such blatant age discrimination exists in GP practices today.
"A person's age should never be used as a factor to determine treatment.
"What a backward system to suggest that people are prioritised solely on the basis of their age, when a 65-year-old may actually be in better health than a 45-year-old."
Gordon Lishman, director general of Age Concern, said: "This survey into the attitudes of doctors is further shocking evidence that age discrimination in the NHS is still rife."
Vivienne Nathanson, head of science and ethics at the British Medical Association, said: "What we have to unpick here is whether it is fair or unfair discrimination, considering what tests or treatments may entail.
"Doctors should be talking to patients about the options open to them."