Since 1979, the French Marine Monitoring network (RNO) has been regularly collecting blue mussels and oysters at some 100 characterized sites along the French shore. The bivalves are used as quantitative bio-indicators of coastal chemical contamination. Since 1981, the collected samples have been stabilized and archived in a sample bank. The sample collection is thus a continuously lengthening record of coastal contamination. Bivalves are collected by the Ifremer coastal laboratories. In order to eliminate their faeces and pseudofaeces, molluscs are depurated for 24 hours in decanted sea water from the sampling area. They are then sized, shucked from their shell and frozen in pools of 20-50 animals. At the Dépt of Biogeochemistry and Ecotoxicology, the samples are thawed, grinded, homogenized, and freeze-dried under contamination-controlled conditions. An aliquot of the powder obtained is devoted to trace chemical contaminant analysis, and the remainder is archived in 100 ml vials and permanently stored in a dark and cool dry place, for future use. This ESB archives about 9000 samples and grows by nearly 100 / year. Three examples of studies conducted using the sample bank are shown.