Only half of people in their mid-30s to mid-40s had a mortgage in 2017, down from two thirds in 1997, the latest data from the Office for National Statistics (ONS) showed.
A third of people in this age group were renting from a private landlord, up from fewer than one in 10 in 1997.
The ONS warned that if the trends continue older people in the future will be more likely to be living in the private rental sector.
And this could have big implications for what life will be like for older people, the body added.
Older people mortgage free
At the same time, older people are far more likely to own a home outright.
Almost three-quarters of people aged 65 and over owned their home without a mortgage, according to the research.
In 1993 the number who had paid off their mortgage was at 56 per cent.
The ONS said over 65s now included people who were the first to benefit from the government’s right to buy initiative, which saw social housing sold at reduced prices and boosted home ownership.
Jim Boyd, chief executive of the Equity Release Council, said: “The UK is ageing rapidly and few can be surprised that 74 per cent of people aged 65 and over own their own homes.
“For those facing a shortfall in retirement income, debt or care costs this provides them with a lifeline as they try and make sense of the financial choices open to them.”