17% of HIV positive people say they have felt suicidal in the last year, according to HIV Ireland.
The survey of people living with the disease also found high levels of stigma remain in relation to HIV among the general public.
It shows 20% of 18-to-24-year-olds thought HIV can be transmitted by the sharing of a public toilet seat.
The organisation is calling for extra funding to increase awareness.
HIV Ireland’s executive director, Niall Mulligan, says he is shocked that so many HIV carriers feel suicidal.
He said: "When we dig behind that, we find that a lot of that is related to stigma and the fact that people are very fearful of being rejected in relationships and by close friends or close family."
He also said younger people clearly need more information.
Mr Mulligan said: "Where things get less positive is in relation to some of the myths that would have come from the 80s and the 90s in relation to HIV being transmitted by, say, kissing or by coughing and sneezing or by a bite.
"Those beliefs are still out there, particularly, interesting enough, more likely to be with younger people rather than older people."