The life expectancy of England's worst off has increased by nearly three years in the past decade, according to a new report.
But more needs to be done to narrow the gap between the rich and poor, the government-ordered review found.
The study, led by Professor Michael Marmot, shows that the difference in lifestyles between the rich and poor has a major effect on the chances of living a long, healthy life.
Although life expectancy for the poorest had improved by an extra 2.9 years, he said more needed to be done to bridge the gap.
The report said: "Reducing health inequalities is a matter of fairness and social justice.
"In England, the many people who are currently dying prematurely each year as a result of health inequalities would otherwise have enjoyed, in total, between 1.3 and 2.5 million extra years of life."
The report called for an overhaul in some areas, including the income tax system.
It said action is needed in six key areas, including giving every child the best start in life, creating fair employment and encouraging people into work, and working to prevent people falling ill in the first place.