There are 644 patients on trolleys in emergency departments, or on wards, waiting admission to a hospital bed, including 14 at two children's hospitals, according to figures from the INMO.
The worst affected hospitals are University Hospital Galway with 55 patients waiting and Cork University Hospital with 54.
Other hospitals badly affected are University Hospital Limerick with 43 patients waiting, Midland Regional Hospital, Mullingar, with 40 and Letterkenny General Hospital with 36.
There are nine patients on trolleys at Our Lady's Children's Hospital, Crumlin, and five at the Children's University Hospital, Temple Street.
Yesterday, the INMO said there were 543 patients on trolleys in hospitals around the country.