SummaryEuropean catfish (Silurus glanis) were tested for their susceptibility to the bacteriumEdwardsiella ictaluri.The LD50ofE. ictaluriwhen injected into European catfish was 5.4 × 106compared to 7.1 times; 104for channel catfish (Ictalurus punctatus).E. ictaluriwas isolated from dead and moribund European catfish and the bacterium was also detected in kidney smears by an indirect fluorescent antibody (FA) technique. The bacterium was not isolated or detected by FA from surviving fish 15 days after injection. No clinical signs ofE. ictaluriinfection were noted in European catfish, but these were prevalent in the channel catfish. These experiments indicate that under experimental conditions European catfish are not as susceptible toE. ictalurias channel catfish