Various phytosociological plant communities may develop on fallowed arable lands depending on soil-and-climatic and topographic conditions. In this paper the Authors have presented conditions under which xerothermic vegetation encroaches on arable lands. Characteristics of fallowed arable lands, which during the diversified in time process of self-sodding changed into xerothermic communities of sward type, was presented on the basis of phytosociological characteristics of selected fallowed arable lands situated in the vicinity of Pińczów and Staszów. It was found, that depending on the substratum, plant communities belonging to various phytosociological units develop on the fallowed arable lands. Communities forming automatically in the initial period of fallowing are characterized by a considerable degree of fortuity. The course of plant succession on fallowed arable lands situated in soil-and-climatic zones favouring xerothermic vegetation advances a development of steppe plant communities through a process of self-sodding. Depending on the geological substratum (gypsums, marls or limestone) and also on the thickness of soil deposit they are diversified in respect of their phystosiociology. ...