We did a retrospective study of 1920 episodes of community-acquired pneumonia (CAP) in 27 community hospitals and analysed inter-hospital variability in length of hospital stay (LOS), mortality and readmission rates. The overall adjusted LOS (mean+/-S.D.) was 10.0+/-9.8 days. LOS increased according to the Pneumonia Severity Index (PSI) risk class: 7.3 days for class I to 11.3 days for class V (P<0.001). In a multiple regression model, LOS increased (P<0.001) according to the hospital (inter-hospital variability), PSI risk class, complications during hospitalization, admission to ICU, need of oxygen and transfer to a nursing home. Hospitals with shorter LOS did not show an increased readmission rate (adjusted OR 1.02, 95% CI 0.51-2.03, P = 0.97) and post-discharge mortality (adjusted OR 1.20, 95% CI 0.70-2.05, P=0.51). There are significant inter-hospital variations in LOS in patients with CAP which are related to differences in clinical management. The reduction of these differences will further improve efficiency and quality of care.