The Holy Father said euthanasia and helping terminally ill people to die early gave people a 'false sense of compassion'.
He was speaking to the Association of Italian Catholic Doctors when he made the comments.
Speaking in the past the Pope said the assisted dying movement was a sign of the "throw-away culture".
Francis also condemned in vitro fertilisation, where an egg is injected with sperm in a laboratory.
He said that was "the scientific production of a child" and " playing with life".
"Beware, because this is a sin against the creator, against God the creator," the Pontiff added.