Over 53,000 people walked out of emergency departments in the first six months of the year before being seen by a doctor.
HSE figures reveal the average number of "did not waits" at EDs around the country averaged 300 per day between the months of January and June.
The HSE says some patients had not been triaged, while others were about to be admitted before they discharged themselves.
Dublin's Mater Hospital recorded the highest amount with 7,215 people, followed by Our Lady of Lourdes in Co Louth and Tallaght Hospital in South Dublin, as reported by the Irish Mail on Sunday.
Main image: A busy hospital. Image: Alamy.