World famous Great Ormond Street Hospital is planning to officially mark its 100th lung and 200th heart transplant on this week.
The children's hospital in central London was among the first in the world to carry out the transplants on children in 1988, and has become the biggest centre of its kind in Europe, carrying out 30 children's heart and lung transplants a year.
The hospital means to use the event to highlight improvements in survival rates and the shortage of donors.
Dr Paul Aurora, a lung specialist at the hospital, says they wanted to thank the families of organ donors for their "great generosity" at a time of personal crisis.
He said at the outset in 1988, the procedures were experimental despite having been performed on adults for a few years previously.
At that time says Aurora there were very few centres in the world doing heart or lung transplants on children.
Though initially they did not know how it was going to work out, over the last 18 years, as well as having helped many children, their results have steadily improved.
The hospital's first heart transplant patient in early 1988 was a boy with congenital heart disease. The operation was carried out along with a transplant team from Papworth Hospital, near Cambridge.
The 100th lung and 200th heart transplant patients will join staff to celebrate the milestone on Tuesday.