Transformations of the natural environment in the area surrounding and encompassing the Vistula River valley during the last 20 000 years BP should be discussed with regard to radiocarbon dating of the organic matter in the documented fossil soils. Part of the 14C dates from horizons A of pedosols in the valley have already been published, for the upper part of the valley by Balwierz & Nalepka , and for the lower part - by Turkowska . Palynologic analysis was also made in many of the documented sites. The most important events in the history of the valley have been supplemented by radiocarbon dating by Starkel . This report presents 14C dates measured in the buried organic horizons of fossil soils in the Middle Vistula valley between Stężyca (Dęblin area) to Liszyno (Płock area). Most datings were made in the Kampinos Forest. For mineral-organic soils the dates lie between 1080 ± 90 Gd. 19S, Laski [Urbaniak-Biernacka 1973] and 12 160 ± 260 [Gd. 4391, Mariew [Konecka-Betley 1991]. In turn, the base of the oldest peat horizon in the Kampinos Forest supplied a date of 10 S90 ± 340 Gd. 2260, Wilków [Konecka-Betley et al. 1991].