Roe deer diet was studied in the floodplain forest of South Moravia, Czech Republic, by analysis of faecal samples collected in six different parts of the study area. Woody plants were the main component of roe deer diet, and they were supplemented with bramble, forbs and grasses through the year. The composition of roe deer diet agreed with its foraging strategy and consisted mainly of browse. Floodplain forest is optimal for roe deer and offers sufficient food sources. Food sources from nearby fields have no influence on the diet of roe deer. The great potential of roe deer to influence the shrub layer is evident. The intensity of impact of roe deer was not affected by availability of other food sources in the floodplain forest. The impact of roe deer on woody plants in this habitat depended mainly on its population density. Therefore, protection and management of floodplain forest is related to the regulation of densities of ungulate species, and not on additional feeding.