NHS workers in Scotland's largest city have been warned against listening to the radio in staff-only areas, including kitchens and porters' lodges.
Thousands of hospital and health centre staff in Glasgow have been told they cannot play CDs or other music because a valid licence is not in place.
The warning comes in a memorandum issued by Glasgow City Community Health Partnership (CHP), which employs more than 3000 staff and is responsible for facilities such as health centres and some hospitals including Gartnavel.
Music in treatment rooms, operating theatres, wards and clinics is allowed, and staff can listen to music through headphones as long as it does not interfere with their work.
But they are prohibited from playing the radio or music in places such as staffrooms and changing areas.
The memorandum, signed by Anne Hawkins, director of Glasgow City CHP, says: "Music is protected under copyright. It can only be publicly played if there is a valid licence in place.
"Such licences are provided by the Performing Rights Society (PRS) for Music in relation to the broadcasting of music to groups of individuals on payment of a fee."
It adds: "The CHP will not purchase a licence for staff only areas including offices (including behind reception desks), file rooms, porters lodges, staff rooms, kitchens, changing areas.
"The broadcast of music in these areas is not permitted as it will expose the CHP and staff members to a claim for breach of copyright."
Matt McLaughlin, Glasgow health organiser for trade union Unison, said the memorandum sounded like an April Fool's joke.
He said: "People are working very hard and to suggest they cannot listen to their favourite radio station in the background to help them to do that beggars belief. People work more efficiently if they are happy at their work. This memo seems a bit bah humbug."
Mr McLaughlin said he would be surprised if artists were seriously concerned about "a couple of porters or half a dozen secretaries" listening to the radio.
In a statement, NHS Greater Glasgow and Clyde said: "Glasgow Community Health Partnership has reminded staff that music is protected under copyright and can only be publicly played in an office or open space if there is a valid licence provided by the Performing Rights Society for Music.
"Licences have been purchased for those areas which are used by patients (where this is deemed appropriate) but it is not appropriate for public money to be spent purchasing licences for staff-only areas including offices, file rooms, porters lodges, staff rooms, kitchens or changing areas.
"Staff can, however, listen to music through headphones or earplugs where it does not present a safety issue or impact on their day to day duties."
PRS for Music, an organisation which represents the rights of songwriters and composers, said when any workspace including a hospital plays music they are required by law to pay for a licence.
It offers exemptions for some parts of hospitals, such as day rooms, patient dining rooms and operating theatres, but licences are required for cafes and staff-only areas.
A spokesman for PRS added: "The creators of music rely on royalties, however small these are, from the use of their music in businesses and organisations across the UK to earn a living and keep creating the music we all enjoy."