August saw a record number of men and women depending on emergency accommodation in Cork, according to Cork Simon.
The homelessness charity said they recorded 679 people - an unprecedented 24% rise in numbers in just twelve months.
Cork Simon said this number is expected to grow over the winter months, as it announced details of its first ever Sleep Out for Cork Simon.
CEO Dermot Kavanagh said homelessness is now impacting every community in Cork and beyond.
"The money raised from the Sleep Out for Cork Simon will help us support a great number of men and women in Cork who are homeless and surviving on the streets of Cork over the challenging winter months," he said.
The charity urged people to raise funds for their emergency services by taking part in the Sleep Out in Elizabeth Fort in the city centre on 10 October or by hosting their own Sleep Out.
Mr Kavanagh said the money raised will help them "support a greater number of men and women in Cork who are homeless and surviving on the streets of Cork over the challenging winter months".
