The food composition, prey size, quantity of prey, feeding frequency and diurnal pattern in the feeding frequency of chicks of Black Stork (Ciconia nigra) were studied in six nests in the Czech Republic during the breeding seasons 1998-2003. Video cameras were used to record prey brought to the nests. Regurgitations and pellets were also analyzed. In total, 474 prey items were collected. Aquatic animals, mainly fish, prevailed in the nestlings’ diet. Six species of fish, undetermined frogs and snakes, two mammal species and eight insect species were found. Adults provisioned their young nestlings with smaller fish. The length of fish and total mass of consumed prey significantly increased with nestling age. No relationship between chick age and feeding rate was found. In total, each chick consumed 14-20 kg of food up to fledging.