The aim of this study was to determine serum antibody levels against the Newcastle disease virus in vaccinated chicken flocks in addition to experimental animals by hemagglutination inhibition (HI) test and enzyme linked immunosorbent assay (ELISA) and compare the results. Methanol-precipitated antigen prepared from the LaSota strain of Newcastle disease virus was used with peroxidase-labelled rabbit anti-chicken IgG as a conjugate and ortho-phenylenediamine as a substrate in ELISA, The negative threshold was found to be an optical density of 0.19 (OD) at a 490-nm wavelength. In addition to the 50 experimental animals, a total of 504 chicken sera (broiler, layer and breeder flocks) collected from 21 farms were tested (both H1 and ELISA). The results of H1 and ELISA were found to be positively correlated, and the t-test was significant in both experimental and test groups (r=0.97 and 0.87 respectively) upon stastical evaluation (p<0.001). All the 504 sera except 1 (0.2 %) demonstrated suitable positivity.