Broilers at 18 days old were vaccinated with a single dose of the K strain of Newcastle disease vaccine administered by different routes. The serological results obtained by haemagglutination inhibition at weekly intervals post-vaccination showed that birds vaccinated intranasally (i/n) or intramuscularly (i/m) had antibody titres higher than those vaccinated by the oral method. Furthermore, when challenged 3 weeks after vaccination, those broilers vaccinated i/n or i/m had 75% and 70% resistance respectively, while those vaccinated by the oral or spray methods failed to withstand the challenge.