Three unrelated severe infections with Streptococcus zooepidemicus occurred in England in 1985. The first patient developed septic arthritis, which has not been recorded before with this organism. The second died with septicaemia, pneumonia and post-streptococcal glomerulonephritis, the only record so far of nephritis following sporadic S. zooepidemicus infection and of nephritis and systemic sepsis in the same patient. The third patient experienced septicaemia during pregnancy but recovered without complications. A likely animal source of infection was found in only one case.