Its territory consists of the provinces of Negros Oriental and Siquijor with the exception of the municipalities of La Libertad and Vallehermoso, and the cities of Guihulngan and Canlaon.

The seat of the diocese is the Cathedral of St. Catherine of Alexandria, which is located at the heart of the city of Dumaguete of Negros Oriental.

On 5 April 1955, Pope Pius XII created the Diocese of Dumaguete with the Apostolic constitution Sanctissima ea verba[2] and appointed the Most Reverend Epifanio B. Surban, D.D.

The Catholic faith was first introduced to the early inhabitants of eastern Negros by the Augustinian Recollect (OAR) friars who established the parish of Tanjay in 1580.

Forty years later, Dumaguete was created as another parish covering the southern territories and Siquijor, which the Spaniards called Isla de Fuego.

[4] It remains a suffragan of the Archdiocese of Cebu, and has for its titular patron St. Catherine of Alexandria whose feast is celebrated on the 25th of November.

Next was Onesimo Gordoncillo (serving from 1974 to 1976), a native of the diocese and one of its own clergy, who later became the third Bishop of Tagbilaran (1976) and then the second Archbishop of Capiz (1986).

[citation needed] On the penultimate year of Modesto's time as the auxiliary of Dumaguete, Rome appointed a coadjutor bishop to aid Surban with the administration of the diocese (1986).

[6] After 11 years of service as the Local Ordinary of the diocese, Lagdameo was appointed fifth Archbishop of Jaro on 11 March 2000.

He reigned for 11 years and made many contributions to the erection of new mission parishes as the renovations of key diocesan edifices such as the Cathedral and the Bishop's Residence.

His greatest legacy is the fiscal reorganization of the diocesan finances and the establishment of the Standard Living Allowance for the Clergy (SLAC) assuring that all the clerics of the diocese would receive an equal living allowance every month regardless of the work assigned to him or wherever the parish he was assigned to.

In December 2024, Archbishop Charles John Brown KC*HS conferred upon nine Papal awardees, the Order of St. Sylvester (Dames and Knights) and Pro Ecclesia et Pontifice at the Dumaguete Cathedral.

For our purpose here, there is no better symbol for the checking of the devil's activities than the serpent's defeat by its mortal enemy in actual life, the secretary bird.