The Holy Father bestowed the church upon Bozanic in 2003 when he appointed him cardinal.
Holy Mass celebrated by Bozanic was attended by numerous priests, nuns, ambassadors and Croats living and working in Rome.
The liturgy was prepared by Giulio Viviani.
Bozanic called on the present to pray for the health of Pope John Paul II. He said the St. Jerome church was an oasis of freedom and the place of gathering for Croats.
Cardinal Bozanic is the 37th cardinal to take possession of the the St Jerome church. He succeeded Cardinal Franjo Kuharic.