Addenbrooke's Hospital in Cambridge has implemented a total smoking ban to encourage healthier lifestyles.
Staff, visitors and patients won't be able to smoke anywhere on site - and there's no longer any outdoor smoking areas.
It also applies to the Rosie Maternity Hospital.
The Trust's Chief Executive Dr Keith McNeil says it's in accordance with national guidelines that hospitals should be smoke free.
"It sends a message that we're not just about treating people here, we want society as a whole to be healthier," he said.
"It's very important from that point of view that we don't condone smoking on the site anywhere."
More top news
Nurses have gathered in Cambridge to campaign to scrap the 1% pay cap imposed on them. The RCN says it's causing nurses to leave.
There will be some early morning sunshine before cloud starts to spill in from the west. Through the late morning showers will then develop.
A 50-year-old man from Cambridgeshire arrested in connection with a fatal crash in Mendlesham has been charged.