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In many areas of Europe there are policies to restore former arable land to grassland. In practice, this usually involves the use of commercial seed mixtures. The abundance of all vascular plants species in 35 ex-arable fields, sown with a commercial seed mixture or spontaneously revegetated, was studied in one landscape area to compare two methods of grassland restoration. Species abundance was also evaluated in the close surroundings of the fields. Data were processed using multivariate (ordination) and univariate statistics. Period of time since abandonment, size of the field and type of grassland restoration (sown vs. spontaneously revegetated) had a significant influence on vegetation. However, for the target meadow species, the type of restoration did not exhibit any influence. After about 20 years the contribution of meadow species that had established spontaneously in the studied fields was similar to that of their surroundings. We concluded that artificial sowing on ex-arable land is not necessary to develop semi-natural grasslands if (i) there are sources of appropriate diaspores in the immediate surroundings, (ii) the site is not very rich in nutrients and (iii) farmers do not need grass production immediately. In these situations and over this timescale natural regeneration would allow substantial savings of money and labour.