OBJECTIVE To assess the pathogen features and risk factors among diabetic patients complicated by lower respiratory tract nosocomial infection.METHODS A retrospective study was carried out to survey the clinical data of diabetic patients complicated by lower respiratory tract infection during from 2002 to 2005.RESULTS The main responsible pathogens were Gram-negative bacteria,their rate was 54.5%.While the rate of Gram-positive bacteria was 35.7 %.The rate of fungi was 9.8%.The risk factors of nosocomial infection included:old age,high level of blood sugar,consciousless status,longtime usage of antibiotics,oxygen inhalation and other aggressive manipulations.CONCLUSIONS In diabetic patients with lower respiratory tract infection,the incidence and mortality were all onrelatively high level.They must be given to pay attention.The chief pathogens were Gram-negative bacteria or fungi.So we should strengthen supervision and avoid risk factors,which are the keys in saving critical diabetic patients.