abstract: The aim of the paper was to analyse the elements of meadow sites water balance in different agro-climatic regions of Poland. The analysis was carried out using mathematical modelling on the basis of meteorological data from growing season in 1970-2004 and from stations: Biebrza, Poznań and Cracow. The estimations were done for 2-cut meadow sites giving the yield of hay equal to 5 and 7 t ha-1 and fed by ground waters with intensity of 0 and 1 mm d-1. Estimations were made for ten-day periods, months, and for whole growing season as a sum of ten-day period values. Potential evapotranspiration was calculated acc. to the crop-coefficient method, as a product of reference evapotranspiraction acc. to the Penman-Monteith formula and coefficient kc. Water deficits for meadows were estimated from water balance of meadow sites, taking into account rainfall, evapotranspiration, useful soil water supplies for plants and ground water feeding. The highest values of water deficits for 2-cut meadows were estimated for the agro-climatic region represented by Poznań station, and the smallest for the one represented by the Cracow station. Water deficits occurred most often in two last months of the growing period at all examined sites. The summarized values of water deficits, since the beginning of the growing period, were the highest in August and September. The results of the study could be the basis for formulation of practical principles of water management on grasslands for protection of peat soils and water resources in small river valleys.