Vegetation and soil seed bank of four neighbouring patches of a semiarid sandy grassland (Festucetum vaginatae danubialae S o ó (1929) 1933) were studied during two vegetation periods. 1. We took coenological descriptions in the patches of the association. Soil samples were taken four times from the patches and seed bank composition was determined by the seedling emergence method. Similarity between the composition of the seed bank and the aboveground vegetation was estimated by the Sřrensen index, showing high similarity in the autumn period and smaller in the spring, probably due to the depletion of the soil seed bank. 2. Density of the seed bank varied from 58 to 3155 seeds/m2, with larger differences within single patches than between the patches. We concluded that the vigorous seed production of a few species is responsible for the extensive fluctuation of the seed bank. 3. Seeds of 88% of the examined annual species and 59% of the perennial species were occurred in the soil samples during two vegetation periods. Out of the 57 species found in the aboveground vegetation, 6 annual (Arenaria serpyllifolia, Cerastium semidecandrum, Erigeron canadensis, Erophila verna, Holosteum umbellatum, Saxifraga tridactylites) and 5 perennial (Euphorbia seguieriana, Festuca vaginata, Minuartia verna, Poa bulbosa, Silene otites) species had persistent seed bank. The association is most vulnerable at the time of early spring and at the beginning of summer, in the period when all species have the less seed reserve in the soil. This calls the attention on the importance of the transient seed bank.