After becoming extinct in the second half of the 20th century, the European beaver (Castor fiber L., 1758) was successfully reintroduced from Bavaria into Serbia during 2004-2005. In the necropsy of an adult female beaver (found dead in December of 2007), we discovered some parasites identified as Stichorchis subtriquetrus in the colon and peritoneal area. This is the first occurrence of the given specific parasite of beavers in Serbia. Decoding of a subcutaneous implanted microchip has confirmed that our specimen was one of the released beavers. We therefore conclude that the parasite in question was reintroduced into Serbia with the beavers originating from Bavaria.