Researchers looked at mortality records and income data for 366,000 people in England who were below retirement age in the first half of this decade, and matched these figures to location.
In the least "green" areas, the difference in the death rate between rich and poor was nearly twice that of places where recreational space was abundant.
The difference was even bigger when it came to deaths from circulatory disease.
The authors, led by Richard Mitchell of the University of Glasgow, say these findings should be borne in mind by urban planners.
"Environments that promote good health might be crucial in the fight to reduce health inequalities," they write.