Up to 546 patients are waiting on trolleys at hospitals nationwide today, according to the INMO.
There are 76 patients without beds at University Hospital Limerick - the worst affected facility.
That is followed by 61 at Cork University Hospital and 56 at University Hospital Galway.
In all, 394 people are waiting in Emergency Departments around the country, while there are 152 in overflow wards.
Three of those patients are under the age of 16.