In Lowicz, Pope John Paul II told an audience of 300,000 that human life is sacred, and that "noone, in any circumstance, can claim the right to destroy an innocent human life''.
Since the fall of communism in 1989, Polish liberals and church-backed conservatives have tussled over abortion, with legislation switching from restrictive to permissive and back.
Currently the law is one of the toughest in Europe, allowing abortion only if the mother's life is at risk, she was the victim of rape or incest, or the foetus is irreparably damaged.
But the Pope made it clear that he was not happy even with this restrictive legislation. ``You are the first guardians and protectors of the life which has not yet come into the world but is already conceived,'' he told the crowd.