More than 100,000 households above the age of 65 are still paying off their mortgages, according to research by equity release lender more 2 life.
Worryingly, 22,000 of the households still making repayments are over the age of 75.
"There is a potential mortgage timebomb ticking with pensioners paying home loans way past traditional retirement ages," says Jon King, managing director, more 2 life.
This is because many households could struggle to pay off their home loans on top of the basic costs of living when their incomes reduce, Kings says.
The rising numbers of pensioners still repaying home loans is explained by the increase in the number of people opting to work past traditional retirement age, and the rise in the average age of first-time buyers.
In total, pensioners are paying £1.36 billion a year to clear their mortgages.