Within the framework of a national survey of spider assemblages of agricultural areas, and co-operating with the research project "IPM of cereals", the arachnofauna of cereals has been systematically investigated in Hungary, since 1992. Samples by pitfall trapping and/or suction sampling took place at 16 different locations, representing five smaller regions of Hungary. As a result over 10000 specimens, representing more than 150 species were caught. The present paper analyses the similarities and differences between the spider assemblages found in the various fields, regarding dominant species, diversity and community structure. It is established, that cereal spider communities in Hungary are dominated by a well defined and limited set of species, which are more or less ubiquitous in every field. These most dominant and widespread agrobiont species are: Pardosa agrestis, Meioneta rurestris, Oedothorax apicatus, Pachygnatha degeeri, Tibellus oblongus. Apart from the agrobionts, cereal fields had a diverse spider community, reaching an estimated species richness of 110 species at several locations. Indicator species analysis showed, that for the cereal fields, as such, there were no strictly specific, indicator spider species. Considering arable fields in general (cereals plus alfalfa) these habitats had few indicator species when compared to natural grassy habitats. These species are mostly native to wetland habitats. We propose that they could became widespread in agricultural habitats, because through dispersal and life history characteristics they became pre-adapted to the ephemeral conditions of agricultural fields.