The stroke death rate in an area of the country has been cut by 40%, according to a new study published in the Lancet.
Strokes occur when the blood supply to the brain is disrupted
The report said preventative medicine and increased management of risk factors by GPs were responsible.
The two-year project in Oxford found the rate had fallen despite a big rise in the elderly population.
The leader of the study said he expected the results would be replicated around the country if a similar nationwide study was conducted.
Strokes occur when the blood supply to the brain is disrupted. In most cases, this happens when a blood clot blocks an artery carrying blood to the brain.
Strokes are the most common cause of death in England and Wales after heart disease and cancer and are the biggest drain on the NHS's resources.
The team, under Dr Peter Rothwell of the Radcliffe Infirmary, compared stroke rates in the county over 2002-2004 with a similar study from the 1980s.
Incidences of a first stroke fell by about 30% in the second study, despite the number of people over 75 increasing by 33%.
For major disabling or fatal stroke, the reduction was 40%.
Dr Rothwell said: "Although we cannot prove conclusively that the major fall in stroke incidence is a direct result of the measured increase in use of preventive medication, a causal link is highly likely.
He told BBC News Online the major credit had to go to GPs, who were recognising more and more that high blood pressure had to be treated early.
The team was careful to have chosen a representative sample, he said.
"Even though Oxfordshire is a relatively wealthy area, we made a point of ensuring that we included patients from deprived areas in our study."
He explained why such a large fall might not be reflected in the national figures.
"The mortality figures are not reliable where strokes are concerned, and not - to an extent - are hospital discharge figures.
"Cancer figures for example are very good, but stroke was often used as a 'dustbin' diagnosis when an elderly person dies for an unknown reason."
He said only an in-depth national study such as this would be able to give a true picture.
The Stroke Association welcomed the study's findings.
"This study shows that preventative approaches against the condition can reduce its incidence," said Dr Joanne Knight, associate director of research and development.
"This is not just in terms of taking medication but also by making simple lifestyle changes such as eating a healthy diet and stopping smoking.
"Adopting these methods will help to reduce the effects of this devastating disease, but will also reduce financial burden on an already overstretched NHS."