Community-acquired pneumonia (CAP) remains a common and serious illness. CAP can be a major cause of morbidity and mortality in elderly patients. This study aims to investigate the precision of disease severity staging scales such as Pneumonia Outcomes Research Team (PORT) Severity Index (PSI) and A-DROP (Age, Dehydration, Respiratory failure, Orientation disturbance, shock blood Pressure) in elderly patients with CAP. For this study, 111 elderly CAP patients admitted to our hospital during a two-year period were recruited and stratified using these scales. We reviewed the precision of the above-mentioned scales in the 111 patients aged 65 years or above, and investigated the disease severity classifications, initial treatment, and clinical course of these patients. The mean age of the patients was 82 (+/-7.6) years. Among these patients, 15% were aged between 65 and 75 years, 50% were older with their ages ranging from 75 to 84 years, and 35% were extremely old with their ages over 85 years. The mortality rates for the patients with the A-DROP score of 0, 1, 2, 3, 4, and 5 were 0%, 0%, 2.2%, 17.2%, 20.0%, and 40.0%, respectively, and those for the patients with PSI class I, II, III, IV, and V were 0%, 0%, 0%, 0%, and 36.0%, respectively. PSI is a useful method for estimating the prognosis in elderly CAP patients. On the other hand, the A-DROP score may be inadequate in terms of judging the disease severity in these patients. With regard to the severity of pneumonia in elderly patients, we should consider not only the A-DROP score but also the underlying diseases such as malignancy, cardiac failure, cerebrovascular disease, liver disease, or renal disease.