A transfer function based on foraminifera has been developed for the Basque marshes. Its geological application allows the interpretation of the sedimentary record corresponding to the last decades and centuries, in terms of palaeoelevation and previous position of sea level, in different salt marshes of the Basque coast. This local information has been compared among different sedimentary records in order to identify the regional signal. This information has been compared also to the instrumental records from diverse tide gauges in the Bay of Biscay. The analysis of this instrumental record shows a sea-level rise rate of 2,08±0,33 mm year-1 for the last 60 years (Santander and San Juan de Luz, 1943-2004 period). Exhibiting a longer time record, geological information in the salt marshes indicates a change in the sea-level rise rate during the first decade of 1900, and allows an estimation of sea-level rise of 1,9 mm year-1 during the 20th century, compared to a stable situation during the previous three centuries.