Pneumonia is a respiratory infection that remains a public health problem and requires appropriate antibiotic therapy. However, irrational use of antibiotics has the potential to increase resistance and worsen patient clinical outcomes. This study aims to analyze antibiotic use among outpatient patients with pneumonia at the X Blitar Health Center using the Defined Daily Dose (DDD) and Gyssens methods. This study employed a cross-sectional approach, utilizing secondary data from 109 medical records and prescriptions for pneumonia patients (ICD-10 codes J12-J18) from February 2024 to May 2025. Quantitative analysis was conducted using the DDD per 1,000 patients per day method, while qualitative analysis of prescriptions was performed using the Gyssens method. The results showed that Amoxicillin (J01CA04) was the most widely used antibiotic, namely 232.42 DDD/1,000 patients per day, followed by Cefadroxil (87.04 DDD/1,000 patients per day), Ciprofoxacin (18.35 DDD/1,000 patients per day), and Azithromycin (15.29 DDD/1,000 patients per day). Gyssens' analysis revealed that most prescriptions fell into categories IIA (33.94%), IVA (29.36%), and V (27.52%). Inaccurate dosage and suboptimal antibiotic selection were the leading causes of irrational antibiotic use. Additionally, 30 pneumonia patients were identified who did not receive antibiotics despite having clinical indications for them. The results of this study emphasize the need for rationalization training in therapy, prescription audits, and strengthening the implementation of clinical guidelines in primary care facilities.