In order to investigate sheep sources of Streptococcus dysgalactiae in flocks affected with joint ill, 10 sheep flocks in England and Wales with laboratory-confirmed cases of infectious arthritis (joint ill) caused by S dysgalactiae were visited during a disease outbreak while a further four flocks were visited during the lambing period in the year following an outbreak. A total of 5239 samples were collected for bacterial culture from 797 ewes and their 1314 lambs. S dysgalactiae was isolated from nine of 894 samples (1 per cent) on farms visited during an outbreak, and from 7 of 4462 samples (0.2 per cent) collected in the year following an outbreak. The 16 samples from which S dysgalactiae was isolated came from the vaginas of eight ewes, milk of one ewe, navels of four lambs, mouths of two lambs and noses of one lamb. In vitro testing of the survival of S dysgalactiae on straw, hay and in water at different temperatures was performed, and it was isolated from these substrates for up to 42, 35 and 0 days, respectively.