People born in the 1960s and 1970s will only be wealthier than the previous generation in retirement if they inherit money, the Institute for Fiscal Studies (IFS) has said.
The think tank found people in their 40s and 50s are less likely to own a home than those 10 years older.
Their incomes are also no higher and their private pensions are smaller.
It suggests an end to the steadily rising incomes and living standards since World War Two.
The IFS analysed the economic circumstances of individuals born between the 1940s and the 1970s.
The only area in which they will be better off than the previous generation is that they are more likely to inherit wealth, with about 70% of those born in the late 1970s expecting to receive an inheritance, compared with 28% of those born in the early 1940s, the IFS said.
While they are more likely to inherit, the benefits will not be evenly spread, with those who are the wealthiest likely to receive the most.
The IFS found that the incomes of working-age adults were no higher in real terms than those of the generation born a decade earlier.
While those born in the '60s and '70s did earn higher incomes when they were younger, they spent lavishly, and so do not have more money saved than the generation before them.
The end of final salary pension schemes means they will suffer in comparison to the previous generation and when they come to claim the state pension it will make up a smaller proportion of their previous earnings.
Rising property prices have made it harder to get on the housing ladder, with home ownership among the '60s and '70s generation falling to about two-thirds, compared with a peak of four-fifths among those born in the 1940s and 1950s, the report said.
One of the author's of the study, Andrew Hood, said: "Since the Second World War, successive cohorts have enjoyed higher incomes and living standards than their parents.
"Yet the incomes and wealth of those born in the 1960s and 1970s look no higher than the cohorts who came before them.
"As a result, younger cohorts are likely to have to rely on inheritances to be better off in retirement than their predecessors.
"But inheritances are unequally distributed, with households that are already relatively wealthy far more likely to benefit."
Inheritance and inequality
IFS director Paul Johnson added: "A lot of that wealth that the older generation have will be inherited by the younger generation - but it tends to be the richer members of the younger generation.
Speaking to BBC Radio 5 live he said: "You start off with this inequality between generations, but what it actually creates, through inheritance, is an inequality within the younger generation."
A government spokesman said it was "committed to protecting pensioners", citing the protection of benefits such as free bus passes and TV licences.
"We are reforming the UK's state pension system to be more sustainable for the future and widening access to a workplace pension," he said.
"These combined reforms will improve the incomes of nine million people currently facing inadequate income in retirement."