The Healthcare Environment Inspectorate (HEI) visited Glasgow's Southern General Hospital as part of its checks on hospitals across the country.
It praised the hospital's work in preventing infections, including information at ward entrances for staff and visitors.
But the report said that the "overall standard of cleaning" at the hospital "could be improved". The inspectors found dusty curtain rails and skirting boards. "Mould was also found on the silicone sealant around several showers, air vents were observed to be dusty and dirty, and some ceiling tiles were stained," the report said.