Poisoning with aflatoxin derived from mouldy bread was confirmed as the cause of death of one dog and was suspected as the cause of death of two other dogs on the same ration. A jaundiced carcass, firm bile-stained liver and haemorrhage into the gastro-intestinal tract were seen at autopsy. Swelling and foamy vacuolation of hepatocytes due to fatty infiltration, marked perioportal proliferation of bile ductules and some periacinar necrosis were the microscopic changes seen in the liver. Aspergillus flavus was isolated from the mouldy bread and also from a sample of vomitus. Aflatoxin B1, 6.7 ppm, was detected in the mouldy bread and extremely high levels of 100 ppm of aflatoxin B1 and 40 ppm of aflatoxin G1 were present in a sample of vomitus.