The occurrence of a living population of the giant deep-sea oyster Neopycnodonte zibrowii is reported on the slopes of Hespérides Mud Volcano Complex in the Gulf of Cádiz, south-western Iberian Peninsula, in 720 m depth. A noteworthy circumstance of this new record is its situation on a sea bottom which was suitable for the operation of a rock dredge and does not apparently feature abrupt cliffs or rocky overhangs as in previous reports on the species.