The 23-month-old child, has been in a coma for over a year and needs a ventilator to keep him breathing due to a rare degenerative neurological condition.
His parents want to take their son to be treated at the paediatric Bambino Gesu hospital in Rome, which is administered by the Vatican.
"Foreign Minister Angelino Alfano and Interior Minister Marco Minniti have granted citizenship to little Alfie. The Italian government hopes that being Italian will allow the immediate transfer of the child to Italy," said a statement from the Foreign Affairs Ministry.
Alfie at the hospital in Liverpool. Photo: ACTION4ALFIE/AFP
On Monday, the director of Bambino Gesu, Mariella Enoc, and an anaesthetist went to the Alder Hey hospital where Alfie is being treated in Liverpool, northwest England, but the establishment's management did not want to meet with them, Italian agency AGI reported.
The case has drawn the support of Pope Francis, who has on two occasions called for the toddler's life to be prolonged.
Evans met with the pontiff in the Vatican last Wednesday, pleading with him to "save our son" in a Facebook post afterwards.
"I want to reiterate and strongly confirm that the only master of life, from the beginning to its natural end, is God, and our duty is to do everything to protect life," Pope Francis said at his weekly audience the same day.
But on Monday, Alfie's parents lost their final court bid in the UK to prevent doctors from turning off his life support.
A High Court judge rejected the appeal by Tom Evans and Kate James for a delay in order to give them time to present a new challenge.
The ruling allowed doctors to withdraw treatment.
Evans' parents wanted the European Court of Human Rights to examine issues surrounding the case, but ECHR judges rejected their bid.
The toddler has been hospitalized continuously since December 2016, suffering from chronic seizures.
On Monday, around 200 protesters gathered outside the hospital shouting, "Save Alfie Evans". A large group then attempted to storm the entrance before being blocked by police.