Early identification of patients with community-acquired pneumonia (CAP) at risk of poor outcome is critical for defining site of care and may impact on hospital resource consumption and prognosis. The Pneumonia Severity Index and CURB-65 are clinical rules that accurately identify individuals at risk of death. However, these scores have some limitations. Therefore in recent years, increasing attention has been being paid to research on biomarkers, since they have the potential to resolve fundamental issues regarding prognostic prediction that cannot be readily addressed using CAP-specific scores. Nevertheless, the use of biomarkers in this context needs to be validated in prospective trials so as to elucidate how they can best be applied in practice. This review examines the usefulness of biomarkers, whether used alone or in conjunction with other clinical severity of illness scores, for identifying CAP patients at risk of short- and long-term mortality and for predicting both the need for intensive care unit admission and the potential for treatment failure.