Evapotranspiration values (ET) are crucial for agriculture where estimates of water reserves available for crops are the basis for scheduling the time and intensity of irrigation, yield prognoses, etc. Detailed evapotranspiration data are, therefore, of essential value. However, stations performing direct measurements of evapotranspiration are very scarcely distributed in Poland, and for this reason the interpolation of data is necessarily biased. Hence, evapotranspiration values are calculated using indirect methods (usually empirical formulas). Data from geostationary meteorological satellites are used operationally for the determination of evapotranspiration with good spatial and temporal resolution (e.g. Land-SAF product). The study of the relation between evapotranspiration values determined with the use of satellite data and those calculated using the Penman-Monteith formula was performed for the study area in Poland. Daily values and cumulated (i.e. decadal, monthly and yearly) values were analysed to determine the quality and possible added value of the satellite product. The relation between the reference ET and actual ET in two consecutive years was discussed, both for the whole test area and for individual stations, taking into account land use and possible water deficit in the root zone, represented by H-SAF (EUMETSAT Satellite Application facility supporting Operational Hydrology and Water Management ) soil wetness index product. The differences are presented and discussed.