Kanianska R.: Buffer systems of Slovak soils - Natural barriers to acidification. Ekológia (Bratislava), Vol. 19, No. 4, 387-391, 2000. This paper describes the trends of the acidification in Slovak soils during the last decades with emphasis on the influence of anthropogenic sources of acidification (acid atmospheric pollutants, fertilizers) and presents buffer systems of Slovak soils acting against acidification. There were determined and mapped three dominant buffer systems according to Ulrich classification in Slovak soils: 1. carbonate, 2. silicate and cation exchange and 3. aluminium.