Our Lady of Lourdes Hospital in Drogheda has been voted Ireland's dirtiest acute hospital in an online poll.
Some 8,000 people responded to the survey on the Rate My Hospital website set up last year by healt webiste Irishhealth.com.
The survey found Mallow General Hospital in Cork to be the cleanest in the country.
Patients or their relatives are asked to rate hospitals on a scale of one to five under a range of headings, including car parking, cleanliness, quality of care, catering and many other areas.
Our Lady of Lourdes Hospital in Drogheda scored an average of 2.39 (48 per cent) for hygiene among the 369 people who completed surveys on services at the hospital, Irishhealth.com said.
Mallow scored an average of 4.20 (84 per cent) among the 49 people who completed surveys on it.
Waterford Regional, in 46th place in the Rate my Hospital table, was the second most unhygienic hospital, with a score of 2.48 (50 per cent) among the 286 people who rated it.
However, the bottom-rated three hospitals in the online survey - Drogheda, Waterford and the Coombe - had relatively high hygiene scores in the 2006 Health Service Executive hygiene standards audit.
In Dublin, the hospitals voted the least hygienic were the Coombe Women's Hospital, in 45th place with a score of 2.63 (53 per cent), followed by St Columcille's Hospital in Loughlinstown, Co. Dublin, in 40th place with a score of 2.84 (57 per cent), followed by the National Maternity Hospital, Holles Street in 36th position with a score of 2.92 (58 per cent).
According to the survey, the cleanest hospitals in Dublin are the Rotunda Hospital in third place with a 3.99 score (80 per cent), Temple Street Children's University Hospital in fifth place with a score of 3.83 (77 per cent), followed by Connolly Hospital, Blanchardstown, in joint seventh place with a score of 3.79 ((76 per cent), followed by Our Lady's Children's Hospital, Crumlin in ninth place with a score of 3.72 (74 per cent).
The cleanest three hospitals nationally - Mallow, St John's in Limerick and the Rotunda - also posted high scores in the most recent HSE hospital hygiene audit in July last year.
Irishhealth.com publisher John Gibbons said the ratings give a "unique insight on patients' and relatives' first-hand experiences of how clean they find hospitals". The rolling ratings system was collated over a nine-month period.
"The HSE hygiene audit, while obviously relevant, is a spot-check on a particular day, the most recent audit taking place over a year ago," Mr Gibbons said.
"Our latest survey results go some way towards providing a more statistically significant patient viewpoint. If patients and relatives believe a hospital is dirty based on what they see over a period of time, rather than a good, bad or indifferent hygiene performance reported by auditors on a particular day, then it is has to be a cause for concern."