Agricultural intensification is a major threat to biodiversity. Agri-environment schemes, the main tools to counteract negative impacts of agriculture on the environment, are having mixed effects on biodiversity. One reason for this may be the limited number of species (groups) covered by most studies. Here, we compared species richness and abundance of 10 different species groups on extensively (0.5 cattle/ha) and intensively (1.0–1.2 cattle/ha) grazed semi-natural pastures in 42 fields in three Hungarian regions. Plants, birds and arthropods (leafhoppers, true bugs, orthopterans, leaf-beetles, weevils, bees, carabids, spiders) were sampled. We recorded 347 plant species, 748 territories of 43 bird species, and 51,883 individuals of 808 arthropod species. Compared to West European farmlands, species richness was generally very high. Grazing intensity had minor effects on α and β diversity, abundance and composition of the species assemblages. Region had significant effects on species richness and abundance of four taxa, and had strong effects on β diversity and species composition of all taxa. Regional differences therefore contributed significantly to the high overall biodiversity. We conclude that both grazing regimes deliver significant biodiversity benefits. Agri-environmental policy at the EU level should promote the maintenance of large scale extensive farming systems. At the national level, the effectiveness of agri-environment schemes should be improved via promoting and using research evidence.