OBJECTIVES: An economic burden of community-acquired pneumonia (CAP) in Japan should be estimated for cost-effective public health services among elderly population. The aim of this study was to calculate direct medical costs associated with CAP. METHODS: A retrospective study was conducted using an administrative database covering approximately 200 hospitals in Japan. The study population consisted of elderly patients (≥65) with a diagnosis of pneumonia (ICD-10 codes: J12-J18) between January 1 and December 31 in 2014. We included patients who had a CAP episode with prescription of antibiotics and pneumonia diagnosis. Treatment periods for inpatient and outpatient services were defined as hospitalization days and days with antibiotic use, respectively. Total direct treatment costs and their fee categories were summarized descriptively. RESULTS: Among edian treatment periods of CAP at inpatient and outpatient were edian treatment costs of at inpatient and outpatient were , respectively. Treatment costs of hospitalization were categorized into fixed costs as a basic fee for hospitalization (59.4%), drug costs (12.3%), and laboratory test costs (14.0%). CONCLUSIONS: A cost driver for CAP treatments seemed to be inpatient services regardless severity of conditions. A public health services to avoid the CAP hospitalization would be important to reduce total treatment costs. We will develop risk factors to estimate high treatment costs and hospitalization risks among elderly population for prioritizing a prevention services such as vaccines.