Last year, 470 people waiting for new organs died while on the transplant waiting list or within one year of being removed from it, including 14 children aged 18 or under.
Of those, 22 adults and 10 children died while waiting for a heart.
NHS Blood and Transplant is using Organ Donation Week, which started yesterday and runs until Sunday, to urge people to strike up conversations with their loved ones to let them know whether they would like to be a donor.
The comments from NHSBT come as a four-year-old girl from Essex is starting school today with a new heart following a successful transplant.
The parents of Evie Doherty praised the family of the organ donor, saying they made a 'selfless decision at a terrible time' which gave their daughter the gift of life.
Figures from NHSBT show that there were 383 heart transplants carried out last year, including 43 involving children under 16.
Anthony Clarkson, NHS Blood and Transplant's associate medical director for organ donation, said: "It's lovely to see Evie going to school thanks to an organ donor.
"Sadly too many children still die waiting for a transplant.
"Please tell your family you want to donate this Organ Donation Week.
"A few words can make an extraordinary difference."
As of August 25, there were 6,414 people on the transplant waiting list - of these, 36 were aged under 18.
For more information about organ donation visit www.organdonation.nhs.uk or call 0300 123 23 23.