Rodents, ants, wasps and flies were found in the Coombe Hospital during inspections over the past 18 months.
Details released under the Freedom of Information Act show the Dublin maternity hospital was forced to close a shower room over rodent sightings.
The Women and Infants University Hospital has spent more than €20,000 on pest-control services.
David Cullinane, Sinn Fein's Health Spokesperson, says it's important there's no impact on patient safety;
"Obviously the cost is significant but it is a problem that has to be dealt with. So in the first instance, everything that can be done has to be done"
He went on to say it is a concern that a room had to be closed "so I think there's a responsibility on management to ensure that the problem is brought under control."
In a statement, the hospital said:
"Reported sightings often take place out of hours. There are then often no sightings at the time of the callout by the pest control technician. The area would still be treated as an affected area because of the reported sighting by using preventative measures. This involves strategically placing traps and/or bait boxes.
"A shower room was closed, decontaminated and deep cleaned. It was rigorously tested by our Infection Prevention and Control team. Measures have been put in place to prevent reoccurrence. No rooms in theatre have been closed during this timeframe."