A flock of 13,951 hens and 1379 cockerels was monitored from 26 to 58 weeks of age for the complex of salpingitis, peritonitis and salpingoperitonitis (SPS). Two hundred and forty-three hens (78 per cent of the hens that died) were examined postmortem, and SPS was recognised by gross examination for inflammatory exudate, in the body cavity or oviduct in 111 (46 per cent) of them. Salpingoperitonitis was the most common form, followed by salpingitis and then peritonitis. There were acute and chronic cases in all three conditions, but only in peritonitis were acute cases more common than chronic cases. Seventeen birds that had died of SPS were cultured for aerobic bacteria within 12 hours of death. Escherichia coli was recovered from a variety of tissues from all of them, and other bacteria, including staphylococci, Mannheimia haemolytica and Streptococcus bovis, were isolated from a few carcases, either alone or together with E coli. Relatively few isolations of E coli were made from normal hens cultured 48, 72 and 96 hours after death.