Galway University Hospital has the biggest inpatient, day case and outpatient waiting lists in the country, with nearly 50,000 patients waiting, according to latest figures.
Its outpatient waiting list is 38,460 and the inpatient and day case list is 10,771.
The latest National Treatment Purchase Fund figures for April show there were 700,830 patients waiting on all lists around the country.
It represents an increase of over 3,000 on March and the overall total now stands at 700,000 for the first time.
Of this, 507 patients are waiting to be seen at an outpatient clinic.
However, waiting lists for inpatient and day case treatments overall have reduced slightly.
There are over 125,800 patients waiting for inpatient, or day case treatment in hospitals.
A further 67,400 are on the 'Planned Procedure ' list - this means that they have received treatment and are due to have additional treatment at a future date.
More than 11,100 patients are suspended from all waiting lists for various reasons, including clinical, personal or social reasons.
The Private Hospitals Association has said its members are ready to assist by providing a wide range of elective treatments.
In a statement expressing disappointment at a further increase in the monthly waiting list figures, the association says the Government needs to redouble its efforts to address what it calls an endemic problem across our public hospital system.
Additional reporting Joe Little
