Objective To investigate the risk factors for respiratory failure in infants with severe pneumonia aged 1～36 months in order to reduce the mortality of inpatients with severe pneumonia Methods Prospective study were conducted on the collected 567 inpatient infants suffering from severe pneumonia from July 1,2000 to June 30,2001 in randomized selected 13 hospitals in Hunan 17 factors were surveyed and analyzed depending on curative effect ( with respiratory failure or without respiratory failure) as variable by single logistic regression and multiple logistic regression Results Single logistic regression analysis indicated that rachitis,congenital heart disease,hemaglobulin,frequently cold,diettherapy,season,evaluation severity score were risk factors relevant to respiratory failure in severe pneumonia Multiple logistic regression analysis indicated that innutrition,hemoglobulin,rachitis,frequently cold,season,evaluation severity score were risk factors associated with respiratory failure in severe pneumonia Conclusion Innutrition,hemoglobulin,rachitis,frequently cold,season,evaluation severity score are risk factors associated with respiratory failure in severe pneumonia