Healthcare workers already had the right to refuse to perform abortions on the grounds of conscience. But a judge said last year that Mary Doogan and Concepta Wood, who work as ward coordinators in Glasgow, could not refuse to participate in planning for the procedure.
A three-judge appeals panel in Edinburgh ruled the right of conscience in the 1967 Abortion Act is much broader, The Guardian reported.
The midwives' lawyer argued they have the right to refuse to participate in abortion in any way except in an emergency where a life is at stake.
"In our view the right of conscientious objection extends not only to the actual medical or surgical termination but to the whole process of treatment given for that purpose," the court said.
The Greater Glasgow and Clyde health board said it is considering whether to appeal. If the decision stands, it could affect National Health Service operations throughout Britain.
Archbishop Philip Tartaglia of Glasgow called the ruling "a victory for freedom of conscience and for common sense."
"I hope that many pro-life health professionals will take heart from this judgment and have the courage to express their own objections if and when they are asked to carry out tasks which are morally wrong and violate their conscience," he said.