This paper presents a first report on current studies on the fens of the Alvar plain of southern Öland. The morphological situation and the basin morphology of the fen of Dröstorps Mose are described (see Maps and Figures). A first modern pollen diagram from an Alvar fen is presented, showing the main phases of the vegetational history of the Great Alvar. After a period of open land from Early Boreal Time (i. e. oldest sediments present) until the later part of the Boreal, there has been a period of denser woodland, obviously covering considerable parts of the present Alvar, lasting until the later part of the Subboreal. The beginning of the new period of open land still lasting is connected with the appearance of cultural, largely agricultural, pollen. The most recent development, since the heavy grazing of the Alvars was discontinued some decades ago, shows tendencies towards reafforestation. The sedimentational history of the fen shows two major sedimentary cycles; strongly calcareous sediments, mainly lake marl, constitute the sequence up to Latest Boreal Time, overlain by detritic or peaty deposits representing the rest of the Late Quaternary.