Every adult in England will become an organ donor from 2020 unless they choose to opt out.
The move comes after organ donation reforms were given the seal of approval by the Queen.
The Bill is known as Max and Keira’s law after nine-year-old Keira Bell’s donated heart saved the life of Max Johnson, 10, following her death in 2017.
Under the legislation, which applies only to England, adults will be presumed to be organ donors unless they have specifically recorded their decision not to be.
The government estimates the change will save hundreds of lives each year, and it replaces the existing voluntary opt-in scheme.
Prime minister Theresa May said she was “delighted” the law has passed.
She said: “It marks a momentous step for thousands of people in need of a life-saving transplant, and could save as many as 700 lives a year.
Police hunt for killers of Shetland pony that was found tied up and beaten in Yeovil
Theresa May tells MPs back my Brexit deal or ‘we will not leave EU for months, if ever’
Archaeologists slam Cadbury treasure hunt that could see prosecutions for trespassing
“With significantly more people willing to consider organ donation than are actually registered as donors, this vital step will presume consent unless people choose to opt out of being a donor.
“It’s important that everyone takes the time to discuss their choices on donation with their families and register their wishes, whatever their preference may be.
“I also want to thank those who have campaigned tirelessly to raise awareness of this issue, and pay particular tribute to Max, Keira and their families for making this historic change happen.”
Jackie Doyle-Price, Parliamentary Under Secretary of State for Mental Health and Inequalities, said: “This is a remarkable change that will make a real difference to so many lives and it has been a privilege to have supported the efforts of so many brilliant campaigners to pass Max and Keira’s law.
“The new system will mean hundreds more lives are saved every year.”
Wales introduced presumed consent in 2015, while Scotland is considering its own reform.
Royal assent is when the Queen formally agrees to make a Bill into a law.
This occurs once a piece of legislation has completed all the parliamentary stages in the Commons and Lords.
Watch the latest videos from Yahoo UK