The Supreme Court of Canada has overturned a ban on physician-assisted suicide, unanimously reversing a decision it made in 1993.
The decision puts Canada in the company of a handful of Western countries where the practice will be legal.
The top court said it would be allowed in the case of consenting adults who are suffering intolerably from a severe and incurable medical condition, though the illness does not have to be terminal.
"We do not agree that the existential formulation of the right to life requires an absolute prohibition on assistance in dying, or that individuals cannot 'waive' their right to life," the court said.
The decision was suspended for 12 months to allow politicians an opportunity to enact new rules surrounding the issue.
A legal challenge to the existing law was brought by the families of two women in British Columbia who have since died, and was supported by civil liberties groups.
One of the women, Gloria Taylor, who had motor neuron disease, died of an infection in 2012. She joined the right to die lawsuit in 2011.
The other, Kay Carter, travelled to Switzerland to end her life, saying before she died that she was terrified at age 89 of "dying inch by inch."
Her family were also plaintiffs.
The court's decision reverses a 1993 ruling in the case of Sue Rodriguez, a pioneer in the fight for the right to die in Canada.
The court at the time expressed concern over protecting vulnerable persons, but in its new ruling pointed to changed social values.
"This is one incredible day," said Grace Pastine, litigation director of BC Civil Liberties Association, which initiated the challenge.
"Physician-assisted dying is now recognised for what it is: a medical service that brings an end, for some individuals, to unbearable suffering."
Parliament can overturn the decision but that is an unlikely outcome.
