Oliba I of Carcassonne was a count of Carcassonne in the 9th century.

He was the son of Bello of Carcassonne

Bello of Carcassonne

Bello was Count of Carcassonne from 790 until his death. He was the founder of the Bellonid Dynasty of Carcassonne and Razes which reached its apex in Wilfred the Hairy, progenitor of the House of Barcelona....

, and brother (or cousin) of Sunifred I of Barcelona. He succeeded to the county of Carcassonne (as well as to the county of Razès

County of Razès

The County of Razès was a feudal jurisdiction in Occitania, south to Carcassonne, in what is now southern France. It was founded in 781, after the creation of the Kingdom of Aquitania, when Septimania was separated from that state.-History:...

) after his brother Guisclafred

Guisclafred of Carcassonne

Guisclafred was the Count of Carcassonne from 810. He was the eldest son and successor of Bello of Carcassonne. His brothers were Sunyer I of Ampurias, Sunifred I of Barcelona, and Oliba I of Carcassonne....

 had died without heirs.

Oliba married to Elmetruda and Richelda, with whom he had three sons: Oliba, Sunifred (who was abbot of Lagrasse) and Acfred

Acfred I of Carcassonne

Acfred I was the Count of Razès from 837 and Count of Carcassonne from 877.Acfred was the younger son of Oliba I of Carcassonne. He inherited Razès on his father's death, while his elder brother Oliba II inherited Carcassonne...

.

After his death the county of Carcassonne was ruled by Bernard of Septimania.