A UK team has been given permission to carry out what would be the world's first full face transplant.
Peter Butler at London's Royal Free Hospital said he was "delighted" to get the go-ahead from an NHS ethics board for an operation "within months".
No patient has been selected for the procedure, although the team has been approached by about 30 patients.
Last November Isabelle Dinoire from France became the first person to receive a partial face transplant.
She had her nose, lips and chin torn off after being mauled by the family dog.
See how the transplant process works
Mr Butler said the go-ahead for the first full face transplant "had been a long journey, but this is just the beginning, really".
"The most important part of the process starts now, which is selection of the patients," he added.
Mr Butler is now looking to draw up a shortlist of candidates who meet the selection criteria for the operation, which includes an assessment of how they will deal with its psychological impact.
His team will select four patients from the UK or Ireland for the procedure, and the operations will be carried out at six month intervals.
He said he would not be able to carry out the operation on children, because of issues of consent.
He said: "These patients will have already undergone reconstructive surgery - perhaps they will have had 50 to 70 reconstructive operations.
"They have reached the end of the reconstructive ladder and there's nothing more it can offer them.
"Then they have the problem of integration into society, of being able to walk down the street in society without anybody staring at them. That's all these people want - to be normal."
The ethics committee at the London hospital looked at whether the surgery and subsequent immune suppression would be safe, and whether any patient would be able to cope with the psychological impact.
Mr Butler has been researching face transplants for several years, looking at issues such as tissue rejection, psychological issues and concern surrounding identity.
The operation will involve removing skin, underlying fat and eight different blood vessels, four arteries and four veins from a donor patient.
The face will then be reconnected to the recipient in a procedure which will last several hours.
After the operation, the patient will have to take immunosuppressant drugs to stop their body from rejecting the new tissue.
Computer modelling carried out by Mr Butler has shown that the recipient of a full face transplant would look different to the donor because of their face shape and bone structure.
Simon Weston, the Falklands veteran whose face was badly burnt during the conflict, welcomed the Royal Free's decision. He told the BBC: "I'm absolutely delighted. This has been long fought for."
Chris Caddy, of the British Association of Plastic, Reconstructive and Aesthetic Surgeons, also welcomed the decision.
He said: "Aesthetic replacement of the deformed or destroyed face has been a Holy Grail for plastic surgeons, with teams across the world exploring all aspects of this challenging process for the last 10 years."
But the Royal College of Surgeons said: "The college still has grave concerns about face transplantation and will continue to advocate a cautious approach."
A spokesman said the college would draw up "minimum requirements" that would need to be met before any transplant is undertaken, and urged the Royal Free to delay surgery until its review had taken place.
And Changing Faces, a charity that supports and represents people with disfigurements, said: "Our main concern is to ensure that any patient who is being considered for this procedure has a full understanding of the risks and benefits."