According to NHS Blood and Transplant (NHSBT), one in four people in the UK have now pledged to donate their organs after death.
In 2001 former health secretary Alan Milburn called for people to sign up to the organ donor register scheme in a bid to double the number from eight million then to 16 million in 2010.
Figures show that at that time 5,532 people were waiting for a transplant, but this has increased to 8,000 - and continues to grow.
Lynda Hamlyn, chief executive of NHSBT, said: "Reaching 16 million on the NHS Organ Donor Register a year before planned is testament to the support that exists for donation in the UK.
"More than a quarter of the population have demonstrated their commitment by signing the register. But, with almost 8,000 people in the UK currently waiting for a life-saving organ transplant we need to do more."
Despite meeting the targets she has urged more people to sign up to help reduce the 1,000 people who die each year while waiting for donor organs suitable for transplant.