The team from the universities of Aberdeen and East Anglia said just one extra trained nurse per 10 beds could significantly boost survival rates.
They said it could reduce the chance of death after 30 days by up to 28%, and after one year by up to 12%.
The research has been published on the eve of World Stroke Day.
The researchers said the best predictor of survival was having the optimal number of specialist nurses in the acute stroke unit.
The data was gathered from an audit of eight hospitals.
'Very clear'
Prof Phyo Myint, of Old Age Medicine at the University of Aberdeen who led the study, said the findings had surprised the researchers.
"We might expect more obvious aspects of health care to have a greater impact on survival, such as, having a team to support early hospital discharge, or the proportion of acute and rehab beds on the unit," he said.
"Instead, we found that, when controlling for all other variables, an increasing nurse to patient ratio has a substantial effect on reducing likelihood of death after stroke.
"This proved to be a very clear and consistent predictor of stroke survival.
"Our figures show that there aren't too many extra stroke nurses required to significantly improve survival - in fact, only one extra trained nurse per 10 beds would see a reduction in mortality at 30 days by up to 28% and up to 12% at one year."
Amanda Cheesley, professional lead for long term conditions and end of life care at the Royal College of Nursing, said: "The importance of having the right number of nurses in place can't be overstated.
"This research echoes findings in other areas of health care where there is a clear link between the number of registered nurses and patient safety.
"It also once more highlights the vital difference that specialist nurses can make. Too often senior and specialist nursing posts have been cut to save money, but their expertise and experience has a measurable positive impact on patients."
The chance of surviving a stroke is linked to the number of trained nurses available to treat patients soon afterwards, according to researchers.