A quarter of Irish adults are worried about being able to afford to keep a roof over their heads, and almost 20% are worried about losing their home.
The findings come from a survey of 2,000 people commissioned by the Simon Communities of Ireland.
The charity hopes the poll results will keep the housing issue at the top of the General Election agenda.
Simon Community spokesperson Niamh Randall said the depth of people's concerns surprised even them.
"Housing and homelessness is one of the major issues of the election campaign, so we're not surprised to see so many people are worried about housing, but we were shocked at the extent of the concern around these issues," she said.
"One in five people are worried about losing their own home and 25% of people are worried about being able to afford their housing costs."