Patients admitted to UK hospitals with community-acquired pneumonia (CAP) require a chest radiograph for diagnostic purposes and to look for complications. This study investigated the association between a chest radiograph performed early in the process of care and clinical outcomes. Consecutive adults admitted with CAP to a large UK teaching hospital trust over a nine-month period were prospectively studied (n = 461). A time to first radiograph of < 4 hours was associated with a significantly shorter median length of hospital stay (LOS) compared with > or = 4 hours (5.75 days versus 7.13 days, p < 0.01). Antibiotics were administered after the radiograph in 89.8% of patients with a time to first radiograph < 4 hours compared with 40.7% of patients with time to first radiograph of > or = 4 hours (odds ratio 12.8, p < 0.001). A chest radiograph performed within four hours of hospital admission for CAP is significantly associated with a shorter hospital LOS and with antibiotic use after chest radiography.