Reservoir competence for the Newcastle Disease virus (NDV) was evaluated in sparrows (Passer domesticus, Linnaeus 1758) captured on a commercial poultry farm and a chicken hatchery in the State of Pernambuco, Northeastern Brazil. A total number of 103 birds collected from a poultry farm (24/103) and a chicken hatchery (79/103) were examined. Hemagglutination inhibition tests, isolation, and viral characterization were performed in all samples collected from each bird. Titers ranging from 1:2 to 1:64 were detectable in 10.68% of sparrows, but positive serology and viral isolation were obtained only from sparrows captured at the hatchery. Hemagglutination activity was inhibited by anti-avian paramyxovirus serotype 1 (APMV-1) serum, and this sample showed an intracerebral pathogenicity index (ICOI) of 0.21, which is similar to the B1 stock vaccine (0.20) used for vaccination in those farms. Therefore, it was concluded that the sparrows were infected by stock vaccine virus, and that these birds could be a reservoir for NDV. However, additional studies involving sequencing of the virus genome of stock vaccine must be carried out.