Benedict, who wore John Paul's vestments for the ceremony, put the beloved former pontiff on the fast track for possible sainthood when he got rid of the traditional five-year waiting period and allowed the beatification process to begin weeks after his death in 2005.
John Paul's beatification is the fastest in modern times, beating even that of Mother Teresa by a few days.
A French nun's inexplicable recovery from Parkinson's disease was decreed to be the miracle necessary for John Paul's beatification.
Beatification is the first major milestone on the path to possible sainthood, one of the Catholic Church's highest honors. A second miracle attributed to his intercession is needed for him to be canonized.
Around the world, Catholics celebrated the beatification, jamming churches from Mexico to Australia to pray and watch broadcasts of the Rome Mass on television.
The Associated Press contributed to this report.