Warsaw's newly appointed archbishop Stanislaw Wielgus resigned ahead of a Mass to celebrate his installation.
His departure followed revelations that he worked with the communist-era secret police.
As the archbishop made an emotional announcement to the congregation, supporters shouted: "No".
Cardinal Jozef Glemp, his predecessor, will temporarily return to his old job.
Cardinal Glemp (r) defended the archbishop, calling him "God's servant".
The archbishop's supporters applauded the cardinal when he warned against passing judgment based on mere documents.
Outside a mainly elderly crowd demonstrated in Archbishop Wielgus' support.