What has emerged and is celebrated today as Nnewi Diocese is no doubt a product of Onitsha Archdiocese. Before now, Onitsha Archdiocese has given birth to several dioceses; for instance, Enugu and Awka diocese were created out of Onitsha Archdiocese in 1962 and 1978 respectively. Nnewi Diocese is another God's gift to the Catholic Church in Igboland. God has graciously blessed that Diocese with a young and dynamic Bishop in the person of Rt. Rev. Msgr. Hilary Okeke a new Diocese. But the creation of dioceses follows the missionary mandate of our Lord Jesus Christ to His apostles to bring the Good news to every nation, race, culture and people. Ever since this mandate, Christians, especially missionaries have continued to bring the light of the faith to different peoples.

This light first shone on the Southeastern part of Nigeria with the arrival of the Holy Ghost missionaries from Gabon to Onitsha under the leadership of Fr. Joseph Lutz late on Saturday December 5, 1885. Fr. Joseph Shanahan (The Apostle of Igboland) joined them in 1902 and when the mantle of leadership fell on him in1905, history was set to record the evangelization of Nnewi Diocese. The stream of this evangelization was to flow through two main courses almost concurrently: one having Nnewi as its source and the other Ozubulu/Ihiala.

Though individuals from various communities have come in contact with the faith as they traveled to Onitsha and other places for trade and in quest of western education, the actual planting of the seed of the gospel in Nnewi Diocese from the Catholic perspective sprang from the treks of Fr. Victor Duhaze to Ozubulu through Oguta (1906) and to Nnewi through Umuoji, Ojoto Mili Agu down to Odida Nnewichi in 1906. However, the Anglican Church was established in Nnewi from Obosi in 1893. But the seed of what is today Nnewi Diocese was sown in 1809. Requests were made by Odida. Community in Nnewichi inviting Fr. J. Shanahan. In the same year, some Ozubulu indigenes had registered the same requests for establishing a Church station at Ozubulu. Thus, on29th January, 1906, the outstation of St. Peter Claver's was opened at Odida Nnewichi by Fr. J. Shanahan who came with Fr. L. J. Ward. This Nnewi station was run from St. Mary's Mission Inland Town Onitsha. The same year saw the arrival of the missionaries at Ozubulu to begin St. Michael's station, Eziora Ozubulu. The Ozubulu Parish was ceremoniously opened on 39th September, 1908, the Feast of St. Michael the Archangel. Fr. Victor Duhaze was the first Parish Priest. From these two centers, the evangelization of what is today Nnewi Diocese was to spread like wild fire.

From St. Peter Claver's Nnewichi, other outstations in Nnewi were opened as follows: St. John of the Cross, Uruagu (1911), St. Peter Claver's Otolo (1914), St. Michael's Umudim (1914-1919), St. James, Ogbe, Otolo (1950) Our Lady of Fatima, Akaboezem (1954 as St. Vincents). However, Nnewi became a Parish in 1933. But from 1931, the Okofia outstanding had served as the “Parish Centre” for Nnewi under Fr. Joe Delany, the first Parish Priest of Nnewi. Until it was moved to Akwugbo, Uruagu under the Late Bishop John Cross Anyaogu in 1935. The Blessed Cyprain Michael Iwene Tansi joined Bishop Anyaogu as his assistant in 1938. The outsations under Nnewi Parish include: Oraifite, Amichi (9 towns in the area), parts of Idemili, Mbano and Njikoka. Oraifite had earlier been evangelized by Fr. V. Duhaze in 1907 after that of Ozubulu. Ako, Ichi station had been opened in 1908 by Fr. Vogler from Trinity Parish, Onitsha. Three outstations have grown into parishes with their first parish priest as follows:
St. John of the Cross Parish, Uruagu Nnewi 1935 [Bishop J. Anyaogu]
St. George's Parish, Oraifite 1979 [Fr. T. Njoku (CMF)]
St. Peter Claver's Parish Otolo Nnewi 1980 [Msgr. J. Nwibegbunam]
St. Joseph's Parish, Okofia, Otolo, Nnewi 1986 [Msgr. A. Anyichie]
St. Michael's Parish Umdim, Nnewi 1987 [Fr. C. Iwuchukwu]
St. Peter Claver's Parish, Nnewichi, Nnewi 1988 [Fr. A. Oburota]
St. Patrick's Parish Ichi 1992 Fr. M. Ndive
Our Lady of Assumption Parish, Nnewi 1996 [Fr. P. Ezeobata]
St. John the Apostle and Evanglist Parish, Akamili, Nnewi 1997 [Fr. Alex Anosike]
St. Martin De Porres Parish, Inyaba, Nnewi 1997 [Fr. L. Asobi]
St. Cletus Parish, Otolo, Nnewi 1997 [Fr. C. Okoye]
Our Lady of Fatima Parish, Oraifite 1997 [Fr. J. Nwakoby]
St. Mary's Parish Oraifite 1997 [Fr. J. Nzekwesi]
St, James Parish, Ogbe, Otolo Nnewi. 2001 [Fr. A. Madu].

The year 1954 witnessed the creation of Amichi parish with the following stations: Amichi, Utuh, Osumenyi, Unubi, Ezinifite, Ekwulumili, Ebenator, Azigbo and Akwaihedi. Before the time, each of the stations had been evangelized and was functioning as either stations of Nnewi or Ozubulu. Thus Amichi was opened in 1910 by Fr. Bubendof after the aborted attempt of Fr. Niech (1909), Ebenator (1913), Ezinifite (1915), Osumenyi (1915), Ekwulumili (1916), Unubi (1916), Azigbo (1930), Akwaihedi (1920), Utuh station was opened in 1913. Among the pioneer Christians was Late Mr. Emmanuel Okeke who was the father of Msgr. Hilary Odili Okeke, now the first Bishop of Nnewi Diocese. These stations have grown to be Parishes as follows:
Our Lady Queen of Heaven (St. Eugenia's) Amichi 1954 [Fr. I. Horking]
St. Patrick Parish, Unubi 1979 [Fr. P. A. Ezeobata]
St. Michael's Parish, Ezinifite 1979 [Fr. I. Umejesi]
St. Peter Claver's Parish, Utuh 1986 [Fr. M. Ozodigwe]
Holy Spirit Parish Osumenyi 1986 [Fr. M. Ifeagwazi]
St. Luke's Ekwulumili 1991 [Fr. M. Ozodigwe]
St. Matthew's Parish, Ebenator 1997 [Fr. JB. Igboka/D.Obi]
St. David's Parish, Azigbo 1998 [Fr. M. Ugwuoji]
St. James Parish, Amichi 1998 [Fr. F. Igboanugo]
St. Anthony of Padual Parish, Osumenyi 2000 [Fr. L. Ikwueke]
St. Mary's Parish, Akwaihedi 2001 [Fr. A. Ndukaji].

From its source at Ozubulu, the second stream of evangelization flowed to other towns where these stations were opened under Ozubulu parish: Ihiala (1908), Okija (1908), Umunuko, Ukpor (1908), Orsumoghu (1906), Mbosi (1910), Isseke (1908), Lilu (1916), Azia (1911). Other substations opened in these towns include: St. Mary's Ukpor Centre (1916), St. Mary's Umuahama Ukpor (1912), St. Gregory's Ihiala (1913), Christ the King, Umuezeawala, Ihiala (1912), Immaculate Heart, Okohia, Ihiala (1914), St. Anthony's Umuohi, Okija (1914), and Sacred Heart, Ogbenabo, Okija (1937). Indeed, the outstations of Ozubulu grew from 40 (1914) to 80 in 1918. By 1926, the Parish had expanded to 102 outstations with Catechist teachers spreading over Mgbidi, Uli, Ihioma, Orlu, Ubulu, Okigwe, Umuahia and Ihiala.

These outstations were run from Ozubulu Center until 1927 when the Parish Centre for some reasons was closed down. It was moved over to Ihiala because the later was in the view of the white missionaries considered to be more central and had a training center for Catechist teachers. However, Ozubulu Parish was re-opened in 1953 and the center was relocated to Amakwa from Eziora while retaining the name St. Michael's because of the people's love for the name. Meanwhile, Ihiala Parish Centre opened other outstations, which are now Parishes in Orlu Diocese and beyond. The Holy Ghost Juniorate at Ihiala was opened in 1952. Thus, today, history has recorded the birth of the following Parishes from this stream of evangelization:
St. Michael's, Eziora, Ozubulu 1909 [Fr. Duhaze]
St. Martin's, Odoata, Ihiala 1927 [Fr. Bindel]
St. Michael's, Amakawa, Ozubulu 1953 [Fr. W. Doolin]
St. Mary's, Orsumoghu 1964 [Fr. Peter Meze]
St. Mary's, Okija Centre 1962 [Fr. Innocent Egbujie]
St. Mary's Ukpor Centre 1965 [Fr. Mac Ivoy]
St. Andrew's, Azia 1982 [Fr. C. Mbaegbu]
St. Gregory's, Ihiala 1986 [Fr. C. Ochuba]
St. Patrick's, Mbosi 1986 [Fr. A. Izukanne]
St. Joseph's, Isseke 1986 [Fr. D. Okafor]
St. Charles Borromeo, Lilu 1986 [Fr. P. Obidi]
St. Joseph's, Egbema, Ozubulu 1991 [Fr. G. Ezanya]
St. Mary's, Umuahama, UKpor 1991 [Fr. P. Ndulue]
St. Anthony's Ihembosi 1992 [Fr. J. Nwabugwu]
Christ the King, Umuezeawala, Ihiala 1994 [Fr. S. Ikwueke]
St. Anthony's Umuohi Okija 1995 [Fr. C. Anene]
Sacred Heart, Ogbenabo, Okija 1996 [Fr. J. B. Okoye]
St. Joseph's, Akwa, Ihiala 1997 [Fr. J. Okogba]
St. Paul's, Ihite, Ihiala 1997 [Fr. A. Madu]
St. Kevin's, Nza, Ozubulu 1997 [Fr. C. Nwankwo]
St. Peter Claver's, Umunuko, Ukpor 1998 [Fr. D. Ojukwu]
Immaculate Heart, Okohia, Ihiala 1999 [Fr. M. Onuchkwu].

Thus, with the official announcement from the Vatican and from the Holy Trinity Cathedral Onitsha of the creation of the Catholic Diocese of Nnewi, the evangelization of this area which stated 95 years ago has given birth to a diocese with 47 Parishes, 129 diocesan Priests, a junior diocesan Seminary, St. Paul's Junior Seminary Ukpor (1967-1971) and Holy Ghost Juniorate within the diocese, a diocesan hospital Our Lady of Lourdes Hospital Ihiala, a hospital Chaplaincy St. Luke's Chaplaincy, Nnamdi Azikiwe University Teaching Hospital, Nnewi, many convents and fraternities for men and women religions, a monastery for nuns - St. Benedictine Monastery, Ozubulu, many Church Schools from nursery to secondary. Such is the level of the ecclesiastical development that Nnewi gives a picture of a new diocese yet it had long existed and lived a “diocese.”

The new Diocese begins to function with the ordinations and installation of Rt. Rev. Msgr. Hilary Odili Okeke as its first Bishop on 10th February 2002. The efforts of Nnewi Catholic Community to build a central Church for the whole of Nnewi have given the new that diocese the Cathedral of Our Lady of Assumption, Okwuana, Nnewi, a cathedral when completed will be one of the biggest and most beautiful Churches in Nigeria.

Today in Nnewi Diocese, there are still some primal religionists (“pagans”). There are equally mainline and Pentecostal Churches. These have their contributions to make in evangelizing Igboland directly or indirectly. But as we march into the third energetic, able and dynamic Bishop team of industrious and committed Priests, a vibrant Catholic Christianity is bound to emerge in Nnewi Diocese.