There were nearly 5,000 call-outs - around 13 a day - made by NHS Trusts to hospitals in England in the year to March 2016.
And, the data obtained under Freedom of Information laws shows, among the sightings were pests spotted on maternity wards, in children’s intensive care units and in operating theatres.
The revelation comes as costs to treat vermin soar, with the amount of money hospitals spent reaching nearly £1.1m - a sum believed to be vastly under-estimated as only 87 out of 150 trusts responded to the request.
Some refused to say how much they had spent, citing private finance initiative (PFI) deals or that the information was “commercially sensitive”.
Costs have risen considerably in the past five years, up more than 26 per cent for those trusts with comparable figures.
Most outsourced their pest-control to contractors such as Rentokil, ISS Facility Services and Medirest and paid for inspections as well as ad hoc call-outs.
In Yorkshire, just four out of 21 hospital trusts provided information. Sheffield Teaching Hospital spent £16,808.90 last year treating infestations, the figures show, compared to £10,494.93 at Dewsbury Hospitals, £4,658.43 in Rotherham, and £7,567 in Mid Cheshire. Figures were not supplied for Airedale Hospital for the year to March 2016, but £6,269.80 was spent the year before.
This compares to spending at Guy’s and St Thomas’ NHS Trust, which almost doubled in the last four years from £67,425 to £132,210 - by far the highest of the trusts which responded.
A spokesman said: “We take all pest control matters very seriously and deal with them swiftly.
“As a large provider of health services in London, the importance of high standards of cleanliness means a robust approach to incidents and prevention is absolutely essential.”
The number of call outs has also risen slightly. A total of 4,885 call-outs were made in the year to March, while like-for-like figures from 57 trusts showed there were 3,880 call-outs in 2015/16, a rise of three per cent over four years.
In Yorkshire, pest control were called out 120 times to Dewsbury Hospital last year, 10 times to Barnsley, 41 times to Rotherham and 167 times to Sheffield Teaching Hospital. At Airedale Hospital, pest control were called out 118 times the previous year.
University Hospitals of Leicester (UHL) NHS Trust and Pennine Acute Hospitals (PAH) NHS Trust had the highest numbers of incidents, each recording more than 300. Pest sightings at UHL, which treats more than a million patients each year, trebled from 104 to 337.
These included cockroaches found in the fifth level of the Infirmary’s Windsor building, which houses the specialist medicine admissions unit and elderly patient wards, rodents spotted in the maternity block and insects sighted in operating theatres at Leicester General Hospital.
Darryn Kerr, director of estates and facilities at UHL NHS Trust, said: “The trust is aware of the problems associated with pest control and contracts are in place for all three acute hospitals to manage the issues effectively, which can often be a result of seasonal problems.”
A Department of Health spokesman said: “Hospitals must have an effective pest control policy and the use of experts is good practice to ensure that buildings are kept clean and safe for patients.”