Seven psittacine birds from an aviary of 35 birds developed respiratory disease and died after the premises were cleaned with a commercial solution of undiluted sodium hypochlorite (5% chlorine bleach). Six birds died within 12 days postexposure, and clinical abnormalities were first observed at 6 days. All 7 birds were necropsied and had gross and histopathologic lesions of the trachea, including epithelial deciliation (7/7), ulceration (6/7), squamous metaplasia (5/7), and epithelial hyperplasia (5/7). These tracheal lesions were consistent with inhalation of a noxious agent. Death in these birds was considered to result from hypoxia secondary to blockage of the trachea or pulmonary congestion and, in some cases, sepsis secondary to invasion of bacteria through the altered tracheal mucosa.