A historical review is given of the stratigraphic and chronological research of the Weichselian glaciation in Finland. Submorainic interglacial organogenic deposits have been found in Finnish Lapland and Ostrobothnia. Radiocarbon analyses give ages of over 50,000 years B.P. and the microfissil assemblages indicate climatic conditions that are more fovourable than at present. Interstadial deposits with radiocarbon ages of 42,000 to over 50,000 years B.P. contain fossil assemblages in dicating a poorer climate than at present. A tentative correlation of the Weichselian stratigraphy by various authors is presented.