rats found in kitchens and ducts underneath a catering department;
rodents and cockroaches found in hospital wards;
maggots in kitchen areas; and,
biting insects in a surgical appliance.
The figures were obtained by the Conservatives. Jonathan Morgan, the party's Shadow Assembly Health Minister, said: "Despite all the extra money being spent on trying to keep Welsh hospitals clean, it is clear it is not being spent in the right way."
He added: "It is clear that nurses need to play a stronger role in ensuring wards are kept clean in between standard cleaning times."
The request for information showed there were 197 call-outs to deal with mice and rats at Cardiff and Vale NHS Trust sites during 2006-07 and 2007-08. This was in addition to 103 call-outs for ants, 156 for insects, and 140 for birds - primarily pigeons, Wales Online reported.
A dead rat was found near the mortuary door at Newport's Royal Gwent Hospital, and silverfish insects were discovered in the kitchen and cafe.
At the city's St Woolos Hospital dead rats were found in ducts underneath the catering department and cockroaches were in the confectionery store between April 2006 and August 2008. Maggots were found at the rear door to the main kitchen, and ants were found in the renal centre and wards.
At Llanelli's Prince Philip Hospital there was a case of biting insects in both 2006-07 and 2007-08. Swansea's Morriston Hospital had 171 call-outs between January 2006 and March 2008.
Jenny Randerson, Welsh Liberal Democrat Health spokeswoman, said: "It's all very well having free prescriptions for millionaires, but cutting back on basic services like cleanliness and maintenance is having its effect on our NHS."
Jonathan Osborne, vice-chairman of the Welsh Council of the British Medical Association, said: "These figures are hard to interpret. Sometimes they reflect the age of the estate - an older hospital is more likely to have pests than a modern one."
However, Richard Jones, deputy director of the Royal College of Nursing Wales, said: "The environment outside ward and clinical areas is beyond the immediate control of nursing staff and the NHS in Wales must ensure there is effective cooperation between clinical and support staff so our hospitals are fit for purpose."
Jonathon Davies, director of operations at Cardiff and Vale NHS Trust said: "Currently, there is major building work being carried out at some trust sites and often this increases sightings of pests especially when ground works are being undertaken. Further, several of our sites are adjacent to parklands which can also be associated with the presence of pests."
An Assembly Government spokesman said: "Hospitals are large, complex buildings and while wholly undesirable and intolerable there is a degree of inevitability that pests will try to inhabit such buildings.
"Pest control programmes include proactive surveillance, including the use of traps and detectors, as well as robust responses to potential or actual infestations. Arguably, the high number of call-outs reflects a proactive approach by organisations to a perennial threat."