An analysis of sedimentation rates during the Holocene in estuaries in the southwestern coast of the Iberian Peninsula using depth/age diagrams reveals the existence of two distinct phases. The first, between ca. 10,000 and 6500 Cal BP, still in the transgressive phase, yields values of sedimentation rates of 5 mm/yr. The second phase extends after the maximum transgressive (ca. 6500 Cal BP) until the present, with sedimentation rates of 1.5-2 mm/yr. These results support the idea that marine sedimentation began during the transgressive phase and continued during the highstand phase, far beyond the time of the transgressive maximum, as postulated in some previous papers. © 2002 Elsevier Science Ltd and INQUA. All rights reserved.