Newcastle disease virus mesogenic (Komarov) strain adapted to BHK21 suspension culture was used as a vaccine. The tissue culture-adapted virus was found to be potent and safe when administered to chicks by the intramuscular route. Potency was assessed by challenge test as well as by serology by haemagglutination inhibition and ELISA tests. The ELISA test appeared to be sensitive, efficacious and correlated well with the challenge test.