Research by national not-for-profit pension scheme NEST found 19% of younger respondents admitting to be completely ignorant on the matter.
Adults across the age range showed a lack of understanding about pensions with 77% failing to know anything about pensions 'in any detail'.
Some 12 per cent said they knew nothing about pensions at all while 63% stated they knew only that they were 'products for retirement'.
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The Nest report said: "NEST's March 2013 consumer survey showed that most people have only a very basic understanding of pensions.
"As we stated in the last NEST insight report, even where there's some basic knowledge this is often flawed and based on misunderstandings and misconceptions centered around what 'investment' means and likely outcomes.
"People's lack of knowledge, understanding, and trust in pensions is what fuels their lack of confidence in future retirement incomes and is the source of the difficulty they have setting expectations for the future."
The study found concern among interviewees about having enough money in retirement with just 9% believing their current and future savings will be enough – down from 14% in a 2011 report.
Researchers found 68% of people welcomed the idea of being put into their company pension scheme through auto-enrolment.
Nest found auto-enrolment opt out rates were lower than originally expected.
Opt-out rates were on average less than 10 per cent, though among older workers this rose to 20%.