From Saturday 1 July until the anniversary, people receiving stamped mail in England will see it display a special NHS 75th birthday postmark (pictured) on the front.
Millions of items of stamped mail are posted each day, so lots of people receiving post in the anniversary week will get to see the postmark.
David Gold, Director of External Affairs and Policy, Royal Mail said: “Like Royal Mail, the NHS serves communities in every corner of the land. The NHS, its staff and volunteers have supported us all for 75 years. We’re delighted to help to highlight the anniversary with this special postmark.
“We would like to take this opportunity to thank everyone in the NHS – from the doctors and nurses to porters and cleaners – for the care and support they give. Happy birthday NHS England!”