The Diocese of Parañaque was erected by virtue of a papal bull by His Holiness, the late Pope John Paul II, on December 7, 2002.  The newly created diocese comprises all parishes within the territorial boundaries of the cities of Parañaque, Las Piñas and Muntinlupa, which were originally part of the Archdiocese of Manila.   The new diocese covers a total land area of 126.5 square kilometers or 48 square miles.   Its communities are a mixture of residential, industrial and commercial districts.
The Augustinians were the first missionaries to arrive in Parañaque.  Notable among them were Fray Diego de Espinar, OSA who started building the church of St. Andrew. Later on, the Augustinian Recollects took over.  Fray Diego Cera dela Virgen del Carmen, OAR built St. Joseph Parish in Las Piñas and the Bamboo Organ for which this parish is widely known.  St. Ezekiel Moreno was parish priest there from 1876-1879.  The Recoletos did much to improve the lives of the people, who were mostly fishermen, in the three municipalities that now comprise the diocese.  Eventually, the fathers of the Congregation of the Immaculate Heart of Mary (CICM) took over the two oldest parishes, that of St. Andrew and St. Joseph.  They, in turn, built schools and improved or preserved the churches originally built by the Recoletos.  The Diocesan clergy took over these two parishes in the 1990’s.

The Church of St. Andrew, which is located in Parañaque City, has been chosen as the See of the Bishop. On January 25, 2003, the Church of St. Andrew was solemnly dedicated and consecrated as the Cathedral of the diocese.  Three days later, on January 28, His Excellency, the Most Reverend Jesse E. Mercado, D.D., was installed the first Bishop of Parañaque, on the very same day the new diocese was canonically established.

Preparations for the First Diocesan Pastoral Assembly began almost as soon as the diocese was established.  During the years, 2003-2004, the diocese embarked on separate consultations with the Clergy, the Religious and the Laity on the development of a pastoral plan for the diocese that is grounded on the current situation but moving towards the vision of what the above-mentioned sectors want to be as a diocese.

The first Diocesan Pastoral Assembly (DPA) was held in February 20-24, 2006 at the St. Joseph Parish in Las Piñas City.  During the assembly, the Clergy, Religious and lay leaders, comprising over 400 delegates met to synthesize the vision-mission of the diocese that developed after a thorough and extensive consultation with various the sectors of the diocese.

In his message to the delegates to the First Diocesan Pastoral Assembly, Most Rev. Jesse E. Mercado, D.D., exhorted the delegates to the Assembly in these words: “I would like to commend everyone who will participate and plan out our diocesan vision and mission together in this Assembly – the lay, religious and clergy, those whose vision, creativity, hard work, openness, collaboration and commitment will lead us in clarifying how we can truly be a Church in this time and age.  I call on each one of you to do your share in exerting your effort to let the love of God permeate the whole assembly.  In our many interactions, we can look each other in the eye and say to each other, “I care for you.  I am your keeper.”  No longer shall we say, “The Church doesn’t care, doesn’t listen and doesn’t act.”  On that day, we stand tall and we stand proud because, by the gratuitous guidance of God, we continue to strive in maintaining our credibility and integrity as a Diocese, as God’s community of disciples.”