Ninety to one hundred and fifty dead birds daily for five successive days were recorded in a broiler farm with total 15000 chicken (32 day-old)in EL- Ayate, Giza Governorate in Egypt. A history of sudden death with respiratory and diarrhoeal signs with a sharp decrease in feed consumption and water intake. Post mortem lesions were air saculitis, perihepatitis, pericarditis with caziated materials in pericardial sac and perihepatic capsule, nephritis, trachitis and haemorragic lesions in cecal tonsils .All vaccination programmes were followed in the farm except missed one gape in using live Newcastle disease (ND) vaccination intervals .This case controlled as the mortality decreased sharply after five days of using specific antibiotic and emergency vaccination. Etiology of this outbreak suggested to be chronic respiratory disease complex which was a combination of viral infection (ND) with a secondary bacterial infection (mycoplasma spp.) as a complicated agent.
