On Pope‟s Day, June 28, 2003, His Excellency Most Rev. Antonio Franco, D.D., Papal Nuncio to the Philippines, presided over the celebration of the Holy Eucharist at the Manila Cathedral.
After communion, His Eminence Jaime Cardinal L. Sin, D.D., Archbishop of Manila, formally announced the division of the Archdiocese of Manila into six new dioceses including the Diocese of Kalookan. He further announced that the first bishop of the new diocese would be His Excellency Most Rev. Deogracias S. Iñiguez, Jr., D.D., then Bishop of the Diocese of Iba.
On August 22, 2003, at the solemn Rites of Liturgical Reception and Canonical Possession, His Eminence Jaime Cardinal L. Sin, D.D., installed Bishop Iñiguez as the first bishop of the Diocese of Kalookan in the presence of the Papal Nuncio, the Archbishops and Bishops of the Roman Catholic Church, the Bishops of Protestant Churches, the Clergy, the Religious and the Catholic faithful.
The Territorial Area of the Diocese of Kalookan
The new Diocese of Kalookan is composed of the southern part of the city of Caloocan, and the cities of Malabon and Navotas. It covers a smaller territory than the former Ecclesiastical District of Cal-Ma-Na. It is bounded on the North by Valenzuela City; on the East by Quezon City, on the West by Manila Bay; and on the South by Manila. It has twenty-six  parishes, one quasi-parish and one mission station.