Sheffield Children's Hospital has assured families it is a "safe place to visit" after one of its buildings failed a fire safety check.
All NHS trusts and foundation trusts were asked to carry out urgent fire safety checks following the Grenfell Tower fire.
The hospital said the cladding is on the top two storeys of the Shephenson Wing on Western Bank but is not an area where patients stay.
A spokesperson from Sheffield Children's NHS Foundation Trust said that they will now be investigating ways of removing the cladding "as soon as possible."
The spokesperson said: "The safety of our patients, their families and our staff is of paramount importance to us.
"Following the national issue emerging around the use of cladding, we have been checking the cladding used on all of our buildings.
"After sending samples of the cladding on our Stephenson Wing for fire safety testing, we have identified material that we will be removing.
"Staff who work in this area are also receiving enhanced fire safety training, and we are working closely with South Yorkshire Fire and Rescue to make sure everything is in place to protect the safety of our patients and staff.
"All fire alarms are fully updated and evacuation procedures in line with best practice.
"We can assure families that the hospital remains a safe place to visit."
The Trust stressed that it is working with their construction company to make sure all cladding installed on its new hospital wing is "the safest material possible," and will be in place before the new wards open.
The Stephenson Wing is a five-storey building on Western Bank. The top two storeys, which are not areas where patients stay, have cladding.
The new theatre block is a two-storey building on Damer Street with the ground floor currently occupied but the upper floor is vacant.
After inspection, the cladding on the Damer Street building was found to be fully compliant and did not require testing.
Buildings at London's King's College Hospital and North Middlesex Trust will also remove cladding on their buildings after they were found to be combustible.
NHS Improvement said it had identified 38 organisations that require extra support to carry out urgent checks and three had failed the rests.
All 38 of these "priority one" trusts have started 24-hour fire warden patrols, it said.