Two-thirds (63%) of those surveyed said they were unable to name the date of the poll which decides Britain's membership of the European bloc.
More than half of those questioned couldn't even say which month the vote is due to take place.
Worryingly, the poll reveals that only half (56%) of students registered only at their term-time address are likely to be there on polling day.
A quarter (25%) who said they are registered only at their university address, confirmed they won’t be there on 23 June.
The findings have prompted action from university managers, who say they will now work flat out to register students to vote.
Nicola Dandridge, Chief Executive of Universities UK who ran the survey of 2,000 students, said the findings were "of real concern".
She said: "While it is good that many students are interested in the outcome of the referendum, it is of real concern that so many are unaware of the referendum date."
It comes as comedian and EU remain campaigner Eddie Izzard is embarking on a huge 31 city tour to persuade young people to vote in June's referendum.
Izzard told the BBC: "Young people need to get registered... two minutes on their smartphone and they can get registered by 7 June."
Richard Brooks, Deputy President of the National Union of Students, said: "The EU referendum is a once in a generation vote.
"We are calling on all students to think ahead about where they will be on 23 June and to register or re-register at that address."
Research has found that younger people are more likely to opt to remain within the EU.
However, they are also known to be less likely to vote than those who are anti-EU.
Andrew Drummond, from pollsters Opinium, told the Observer: "Young people are much more pro-EU but much less likely to bother voting, meaning that a key element of Remain’s coalition is looking flaky."