PEST control inspectors were called to the Royal Bolton Hospital following reports of mice droppings in a linen room, ants in a kitchen and thread worms in a dishwashing area.
Each year, Bolton NHS Trust pays a pest control team £3,628 to keep problems at bay.
They were called to the hospital 17 times in 2009, 20 times in 2010, 20 times in 2011 and 31 times in 2012.
Hospital bosses and staff stress it is “inevitable” there would be some insects found on the site as it was surrounded by open land and that any possible sightings are dealt with “promptly”.
Last year, mice or mice droppings were spotted five times and pest controllers set traps in most cases.
In July, a dead rat was found and rat droppings were seen in the children’s outpatients area in April, 2012.
There were three sightings of ants last summer, in the renal dialysis unit kitchen, the ante-natal outreach area and in the Shawcross House kitchen.
On three occasions, wasps or bees were reported and a beekeeper was brought in last May to remove a swarm of bees.
There were also reports of little black flies in the telephone access centre, biting insects in E5 Ward, in the main theatre coffee room and in the accommodation unit block 2, and reports of biscuit beetles in the day-care unit kitchen.
Pest controllers put traps and bait down when staff reported a squirrel in the education centre roof space last October.
A live pigeon was removed from the coronary care external courtyard last September.
A trust spokesman said: “Any large public site and buildings are likely to have some level of problem with pests. We encourage our staff to report problems.”