The controversial archbishop of Warsaw has resigned, less than an hour before he was due to be installed in his post, the Vatican has said.
Stanislaw Wielgus has been at the centre of communist-era spying row.
A special Mass had been planned for his installation on Sunday, despite his recent admission that he had collaborated with the secret police.
The statement, by the Vatican's mission in Poland, said Pope Benedict XVI had accepted the archbishop's resignation.
The Pope has asked Cardinal Jozef Glemp, Archbishop Wielgus' predecessor, to return to his post temporarily "until further decisions have been taken concerning the archdiocese", the statement added.
Commentators say a decision to stop the archbishop's installation at this very late stage is unprecedented.
Poland's president had been expected to attend the event.
Opinion divided
The archbishop's appointment had been described as the most serious crisis in the Polish Church in recent times.
The decision to appoint him divided opinion in the staunchly Catholic country.
In one survey, two-thirds of people asked, said Archbishop Wielgus should resign.
His admission came after a Church commission acknowledged he had collaborated with the communist secret police.
Archbishop Wielgus said he had had contacts with security agents, but denied informing on priests.
He said documents suggesting otherwise were drawn up only by communist "functionaries".
Our correspondent says that in a country where the Catholic Church plays such an important role, this scandal could hardly have been more shocking.
Pope Benedict XVI made the appointment last month.
Just before Christmas, the Vatican released a statement insisting the Pope had been fully briefed on Archbishop Wielgus' past and supported his appointment.
The Church plays a very prominent role in Polish society and was highly esteemed because of its leading role in the fight against communism in Poland and worldwide, particularly during the time of Polish Pope John Paul II.
But historians estimate that up to 15% of Polish clergy agreed to inform on their colleagues in the communist era.
Photo caption
The new Roman catholic Archbishop of Warsaw, Stanislaw Wielgus