The aim of the study was to determine the aetiologic agent causing deaths in two flocks of Pekin ducklings at the age of 12 d in Poland. on the basis of clinical symptoms and pathological changes, viral hepatitis infection was suspected in the birds. During the necropsy, liver sections were collected, from which total cellular RNA was isolated. Then, real-time polymerase chain reaction (RT-PCR) was performed using primers complementary to the pre-S region of the duck hepatitis virus genome. In all liver samples, the presence of a 530 bp PCR product was detected. The RT-PCR demonstrated the presence of genetic material of duck hepatitis virus type 1 (DH type 1) in the examined ducklings.