Organic-rich sediments are exposed at a number of onshore and nearshore sites along the Baltic Sea coast of the Curonian Spit. Radiocarbon dating of relict tree stumps, as well as buried and reworked peat and palaeosols, found along the Russian part of the Curonian Spit (villages of Lesnoy and Rybachy) and in the vicinity of Zelenogradsk indicate the formation of these sediments over a wide time period from 7300 cal BP to 300 cal BP. Organic-rich sediments of different stages of the Holocene sand barrier evolution are of interest in terms of environmental protection, as potential accumulators of oil (or other hydrocarbon) pollution and indicators of intensity of coastal erosion. In terms of geochronology, the data have implications for reconstructing the geological history of the Curonian Spit and Curonian Lagoon during the Late Pleistocene and Holocene.