The number of patients admitted with community acquired pneumonias (CAP) varies greatly from one hospital to another. Prognostic models for CAP can help physicians decide which cases to treat on an outpatients basis. Our aims were: a) to validate a model for predicting low-risk CAP, and b) to estimate savings that would have resulted if the low-risk patients identified by the model had been treated at home rather than in hospital. The prediction rule of Fine et al. was used to classify retrospectively 260 CAP patients. Mortality in each category was compared with the mortality predicted. Patients in the lowest risk categories were considered to have been inappropriately admitted. The predictive model used has been found useful for identifying patients at very low-risk of dying from CAP. Application of the model can lead to savings.