The Irish Nurses and Midwives Organisation claims 2018 was the worst year on record for hospital overcrowding.
INMO claims 2018 worst year on record for hospital overcrowding
New analysis from the organisation said 108,227 patients went without hospital beds last year - a record high.
The figures are a 9% increase on 2017, which was itself a record high.
This is nearly double the number in 2006 (55,720), when INMO records began.
The months with the highest figures last year were January (12,201), February (10,772) and March (10,511).
The worst-hit hospitals included:
Limerick University Hospital - 11,437Cork University Hospital - 9,135Galway University Hospital - 7,452Midlands Regional Hospital, Tullamore - 5,831Tallaght University Hospital, Dublin - 5,432
Smaller hospitals also saw record overcrowding, the INMO says; South Tipperary General Hospital had 5,201 patients on trolleys this year.
It blames overcrowding on low capacity and understaffing.
The organisation said it has asked the Government to work with it to try to resolve problems with recruitment and retention in nursing.
It says this has not happened, and that 95% of INMO nurses and midwives voted in favour of industrial action.
The INMO executive will meet next week to set dates for strikes.
INMO General Secretary Phil Ní Sheaghdha said: "Despite the Government spin, 2018 was the worst year on record for overcrowding.
"Negative records were set throughout the year, with over 100,000 admitted patients forced to wait on trolleys and chairs, without a proper bed. We know that this dramatically worsens outcomes for our patients.
"The health service does not have enough beds to support our population. More beds means more nurses, but the HSE simply can't hire enough on these wages. It's beyond time for the Government to engage proactively with the INMO to resolve the crisis in Irish nursing and midwifery.
"Patients should be focused on recovering, but instead have to worry about waiting times, understaffing and a lack of beds. 2019 must see real changes in policy and funding to resolve this once and for all."
Meanwhile, HSE figures put the number of patients on trolleys in emergency departments today at 236.
The 'TrolleyGar' count taken at 8am shows there were 24 patients waiting over 24 hours and 94 patients waiting over nine hours for admission.
The HSE says the overall figures represent a 45% decrease on the same day last year.
Unlike the INMO data, the HSE figures do not include patients placed on wards waiting for admission to a bed.