12,827 people are registered as homeless in the State.
The total includes a record number of children for the second month in a row.
3,904 children are growing up in B&Bs and Hotels according to the figures from the Department of Housing.
The figure for September is an increase of 136 on August's total.
While it is 16 percent higher than the number of people registered as homeless in September 2022.
The issue is most acute in the capital with 9,391 people in emergency accommodation - including more than 2,966 children.
The figure is 1.3% higher than the previous month, and an increase of 21% over the same period in 2022.
The figures from the Department of Housing do not include rough sleepers, women in refuge centres, refugees or asylum seekers, or the so-called hidden homeless.
The number of people living in emergency accommodation in September were released by the Department of Housing this afternoon and showed that in the Dublin region alone there were 9,391 adults and children – 1.3% more than the previous month, and an increase of 21% over the same period in 2022.
Dublin Simon CEO, Catherine Kenny, says: "These grim statistics come as we are facing the most difficult months of the year where we traditionally see an increase in people entering homelessness. I am fearful of what is yet to come this winter as there is no indication that the numbers of people entering homelessness is going to decline any time soon.
"In June 2016 just over 6,350 people were homeless nationally, we are now in a situation where it is 100% higher than just seven years ago. The figures in Dublin alone are now higher than national figures in 2016, these are the kind of grim records that we need to put behind us.
"With the recent announcement of a budget that did little for people facing the reality of homelessness, we are in a situation where only the sustained delivery of housing and tailored supports can truly end the threat and the experience of homelessness for so many people in Ireland."