Newcastle disease (ND) is the first most economically important endemic viral disease ofrnchickens that has a potential threat to village chickens and commercial poultry farms inrnEthiopia. Reports from NVI Sales and Customer service directorate evidenced thatrncustomers are complaining against the effectiveness of lentogenic ND vaccines.rnTherefore, this study was designed to isolate and molecularly identify Newcastle diseasernvirus and to assess the protective efficacy of ND vaccines against the current circulatingrnviruses. The study was carried out from December 2019 to May 2021 in Adaâ€™a district;rnBishoftu town and Dhankaka village. A Cross-sectional study method was used torninvestigate ND in suspected cases and a total of 52 samples were collected for virusrnisolation and virus gene detection. ND virus was isolated in specific-pathogen-free (SPF)rnembryonated chicken eggs and virulence of the isolates were determined in vitro and inrnvivo. The current findings confirmed the circulation of virulent strains of ND virus in thernstudy areas. The isolates were further identified by molecular assay, targeting thernamplification of avian paramyxovirus-1 (APMV-1). Vaccine protection efficiency wasrnevaluated in chickens hatched from SPF eggs. The chickens were selected randomly andrnassigned to five experimental groups. Experiment groups were vaccinated by thernlentogenic vaccines (HB1, Lasota, and I-2) produced in the National Veterinary Institutern(NVI) using 106.5Embryo infective dose (EID)50 per chicken at day zero (age of 7 days),rnand boosted at days 14 and 35. Group 1 was vaccinated by HB1 on day zero, revaccinatedrnusing Lasota on day 14 and boosted by Lasota on day 35 (HB1-Lasota-Lasota). Similarly,rngroups 2 - 4 were vaccinated, and boosted as (HB1-I2-I2), (I2-Lasota-Lasota), and (HB1-rnI2-Lasota) vaccines, respectively while group 5 were unvaccinated and threated as arncontrol group. On day 49 all treatment groups were challenged by â€˜Dhankakaâ€™ ND virusrnisolate with 106.5ELD50 per chicken through occulo-nasal route. The result indicated thatrnchickens in group 1 were induced a protective index of 94%, chickens in groups 2, 3, and 4rnwere revealed 100% survival while chickens in the unvaccinated group were all dead.rnHence, the current ND vaccines produced at NVI induced an immune response against therncirculating virulent ND virus using vaccination-boost-boost and challenge protocol inrnexperimental SPF chickens challenge.