A record 13,179 people are registered as homeless in the state.
Department of Housing figures show it also includes a record number of children growing up in hotels and B&Bs.
Never before has the Department of Housing reported more than 13,000 people living in emergency accommodation.
The total for October is 15% higher than the figure a year ago.
3,991 children are growing up in B&Bs and hotels - with homeless charity Focus Ireland describing it as a "disgrace".
In Dublin - the issue is most acute - where there are 9,713 people registered as homeless - including more than 3,000 children.
The figure from the Department of Housing doesn't include rough sleepers, women in refuge centres, asylum seekers or refugees, or the so-called hidden homeless.
Focus Ireland says it is disgraceful that almost 4,000 children will be homeless this Christmas.
Figures published by the Department of Housing today show a record total number of 13,179 people officially homeless in October 2023. This is an increase of 352 compared to the previous month and an annual increase of 16% compared to October 2022.
The new figures show that the number of children homeless in Ireland has reached yet another record high, with 3,991 children currently without a place to call home, an annual increase of 15%.
Focus Ireland Director of Advocacy, Mike Allen said: "There is much good work being done every day by Focus Ireland, other NGO’s, and the State to prevent and end homelessness but we have to say it really is a disgrace that 4,000 children will be homeless in Ireland this Christmas.
"It is heartbreaking to know that some of these children are only babies and will be spending their first ever Christmas homeless.
"Ireland is not a poor country; this should not be happening, and we must always remember that homelessness is not inevitable and can be prevented by the right policies."