An outbreak of fowl cholera in a broiler-house with 6,000 six-week-old broilers is reported. The birds were affected with respiratory disease when they were four weeks old. Eight days after recovery, at an age of six weeks, 50 per cent of the birds were severly ill. The birds were reluctant to move and unable to drink. Four hundred birds died in one day. Post-mortem examination revealed marked swelling of the kidney and arthritis of all the hocks and knee joints in all fifteen birds studied. Pure cultures of Pasteurella multocida were isolated from all joints, the heart, the liver and the kidney. Treatment with chloramphenicol resulted in recovery of the birds which were slaughtered under the supervision of the Veterinary Services of the Ministry of Agriculture and Fisheries in the Netherlands. The disease was not observed in the two other broiler-houses on the same farm, which housed 11,000 and 12,500 broilers of the same age. The findings are discussed.