An enzyme-linked immunosorbent assay (ELISA) for monitoring antibodies specific to Bordetella bronchiseptica in guineapigs and rabbits was developed. In conventional and SPF colonies of guineapigs and rabbits, the ELISA was equally successful in detecting infected animals when compared to selective cultivation from the respiratory tract. The ELISA showed a sensitivity of 100% and a specificity of 90% in guineapigs. In rabbits the sensitivity and specificity of the ELISA were 97% and 91% respectively. In rabbit sera from infected colonies, ELISA activity showed a statistically significant correlation with titres obtained in the micro-agglutination test. Since serologically unrelated strains of the bacterium exist, the monitoring of animals for B. bronchiseptica infection by ELISA should be performed with various antigens.