The Duke of Edinburgh told a Filipino nurse her country must now be "half-empty" as "you're all here running the NHS" during a visit to Luton and Dunstable University Hospital on Tuesday.
Philip, who is famed for his gaffes, made the hospital worker from the Philippines laugh with his comment during a visit to open a cardiac centre.
A spokeswoman for the hospital described the royal visit as a huge boost for staff morale and said the Duke was in a jovial mood, making jokes throughout his tour.
Philip had a stent fitted to clear a blockage in a coronary artery in December 2011 and when, during the visit, he was given a gold plated stent, he quipped that he now had a spare.
The Duke is well-known for his outspoken comments and famously told British students during a 1986 state visit to China: "If you stay here much longer, you'll all be slitty-eyed".
He also once told a group of deaf youngsters: "Deaf? If you are near there, no wonder you are deaf," referring to a school's steel band.
He also told Susan Edwards, who is blind, uses a wheelchair and has a guide dog: "Do you know they have eating dogs for the anorexic now?"
The hospital spokesman said of Tuesday's visit: "Staff greatly enjoyed the opportunity to meet the Duke of Edinburgh, and we regard all personal conversations he had with our staff and guests as private and therefore would not comment on them."
Buckingham Palace said it did not comment on private conversations.
"Deaf? If you're near there, no wonder you are deaf."
- To a group of deaf children standing next to a steel band.
"It looks like the kind of thing my daughter would bring back from her school art lessons."
- At an exhibition of 'primitive' Ethiopian art.
"People usually say that after a fire it is water damage that is the worst. We are still drying out Windsor Castle."
- To survivors of the Lockerbie bombing.
"You look like you're ready for bed!"
- To President of Nigeria, who was wearing national dress.
"During the Blitz, a lot of shops had their windows blown in and put up notices saying, 'More open than usual'. I now declare this place more open than usual."
- At Hertfordshire University.
"Well, you'll never fly in it, you're too fat to be an astronaut."
- To a 13-year-old child, while visiting the space shuttle.
"You are a woman, aren't you?"
- To a woman in Kenya.
"You can't have been here long, you haven't got a pot belly."
- To a tourist in Budapest.
"Are you all one family?"
- To <em>Britain's Got Talent </em>winners Diversity.
"I thought it was against the law for a woman to solicit."
- To a woman solicitor.