By studying 36 boreholes in the Lower Segura Basin (eastern Betic Cordillera) we identified a stratigraphic unconformity at an average depth of 30 m. The most recent sedimentary unit filling the basin, consisting of fluvial flood plain and coastal deposits, lies on this unconformity. The age of the unit was established on the basis of 30 absolute 14 C datings, which indicate that the uppermost 20 m were deposited from 8,000 yr B.P. to the present. The estimated sedimentation rates range from 3.7 mm/yr for the period 8,000-6,000 yr B.P. and 1.9 mm/yr between 6,000 yr B.P. and the present. The first interval represents an episode of high sedimentary aggradation, interpreted in a context of rapid sea-level rise, whereas the second is characteristic of relatively low aggradation related to sea-level stabilization.