This study was performed on 4 broiler chicken farms (20.000, 24.000, 25.000 and 30.000 bird) in Sharkia province. Birds of these farms suffered from respiratory manifestation and swollen head. Their ages 44 days. Bacteriological and pathological to 30 from ranged 294 Assiut Vet. Med. J. Vol. 52 No. 109 April 2006 examinations were done. Clinically, the affected examined chickens were suffered from facial edema, conjunctivitis, closed eyes and swollen head. Macroscopically, edema in the face and sinuses, cyanotic head, mucous exudate in nares and trachea was seen. Lungs were congested with area of consolidation. Bacteriological examination revealed the isolation of Ornithabacterium rhinotracheale (ORT) which was identified by biochemical reactions. Histopathologically, face skin was suffered from edema with leukoytic infiltration mainly heterophils, lymphocytes and macrophages. The trachea showed tracheitis together with fibrinous or mucous exudates. The tracheal mucosa was thickened by inflammatory cells mainly heterophils with exudates within tracheal lumen. Bronchitis of the secondary bronchi were common. The lungs showed pneumonia with the presence of air sacculitis. Pericarditis, with leukocytic aggregation and edema was seen. Liver showed coagulative necrosis and portal leukocytic infiltration. Lymphoid depletion of the spleen also was noticed. This study investigate the role of ORT as a field respiratory problems among broilers.