Clifford Whittaker, 88, from Colchester, was diagnosed with Type 1 diabetes when he was eight years old.
He was awarded the medal by the charity Diabetes UK which described him as "an inspiration".
"My diabetes has never stopped me doing anything," said Mr Whittaker, adding he had only stopped driving two years ago.
If poorly managed or left untreated, diabetes can lead to blindness or amputations.
Mr Whittaker said he had managed to live with the condition for so long thanks to his late wife Doreen, to whom he was married for 60 years.
The couple met while working in a sweet shop in Hertfordshire.
He said: "Doreen passed away six years ago. But she used to look after me very well and make sure I was eating properly and generally looking after myself," said Mr Whittaker.
300,000
people in the UK have Type 1 diabetes
10%  of all diabeties is Type 1 - where the pancreas doesn't produce any insulin
40 Most people are diagnosed in their childhood and before they reach the age of 40
"My diabetes has never stopped me doing anything and people have always been very kind. I worked in the wages department of a company until I retired in my 60s."
Sharon Robert, of Diabetes UK said: "He is an inspiration, and has really shown that through managing your diabetes well you can live a long and healthy life".
Mr Whittaker was given an HG Wells medal which is awarded to people who have lived with the condition for 80 years.
Novelist HG Wells co-founded the Diabetic Association - now Diabetes UK - with Dr Robert Lawrence in 1934. They both had the condition.
A pensioner who has lived with diabetes for 80 years has become the first person in the UK to get a medal for the way he has coped with the condition.