Ten brown layer parent hens were injected intravenously with arthropathic and amyloidogenic Enterococcus faecalis at 27 weeks of age to assess its vertical transmission during the subsequent 6-week production period. All inoculated hens developed chronic bacteraemia and arthritis, four died due to septicaemia and two of the remaining six showed amyloid arthropathy. The egg production was maintained at a lower level than the controls. Of eggs collected during the first 2 weeks after inoculation, E. faecalis was re-isolated from the yolk sac of 76% (13/17) of infertile eggs and dead embryos detected at the 18-day candling, and 100% (6/6) of non-hatching eggs, and from arthritic joints of 3% (2/66) offspring chicks of the same batch, although the latter did not develop joint amyloidosis by 8 weeks of age. E. faecalis was also re-isolated from ovary and oviduct of parent birds that died due to septicaemia. The E. faecalis organisms re-isolated from blood, ovaries and joints of diseased parent stock, yolk sac of infertile eggs and dead embryos detected at the 18-day candling, and non-hatching eggs, as well as organs and joints of offspring, had the same pulsed-field gel electrophoresis patterns as the E. faecalis isolate used to infect the parent birds. These findings indicate that vertical transmission of arthropathic and amyloidogenic E. faecalis may occur on a small scale.