In 1989-1991 the epigeic spider communities were studied at nine localities on the area of the waterworks Gabčikovo. A total of 118 species, belonging to 19 families were found. Pirata hygrophilus was the characteristic species in the spider communities of the regularly inundated floodplain forests. In softwood floodplain forests, where humidity conditions have changed, we recorded an increasing abundance of species Pardosa lugubris. Ozyptila praticola, Diplostyla concolor. Pachygnatha listeri. In the spider communities on the observed localities the species from the family Lycosidae predominate. The communities were characterized by relatively low values of diversity (from 1.79 to 2.63). Concerning their araneofauna till 1991, the localities Královská lúka, Dobrohošl and Klúcovec belong among the most preserved biotopes from the observed areas.