A new publication shows that UHG and Portiuncula Hospital are at opposite ends of the scale when it comes to outpatient waiting times.
University Hospital Galway has the most patients waiting for appointments, while Portiuncula Hospital in Ballinasloe has the fewest.
That's according to health service productivity data and insights published by Minister for Health, Stephen Donnelly.
The data published provides details of healthcare investment, workforce, activity and performance across the health service.
It shows that University Hospital Galway has the highest number of people waiting for a first outpatient appointment, at 48,000.
While on the opposite end of the scale, Portiuncula Hospital in Ballinasloe has the fewest in the country, with 3,000 patients waiting there.
UHG is also among the worst hospitals for waiting times for patients who need an overnight hospital bed for treatment such as surgery.
In response to the publication, the Irish Medical Organisation says is it increasingly concerned about waiting list numbers and the lack of capacity in the system.
It adds that something needs to be done to address the chronic shortage of bed capacity and the ongoing recruitment freeze.
