Aging of the population has led to an increase in the prevalence of cancer among older adults. In Japan, single agent chemotherapy was recommended for advanced non-small cell lung cancer (NSCLC) for those, who were aged ≥75 years, while the Western guidelines did not recommend a specific regimen. In clinical practice, physicians are required to decide the treatment based on a lack of enough evidence. This study aimed to examine the prescribing patterns of first-line chemotherapy according to age in the real-world practice. Data from the survey database of Diagnostic Procedure Combination and hospital-based cancer registries of designated cancer centers nationwide were used. The first-line chemotherapy regimens among 9,737 patients who were diagnosed with advanced lung cancer between January and December 2013, were identified and compared based on age. We found that the proportion of patients receiving chemotherapy decreased with age; 80.0%, 70.4%, 50.6%, and 30.2% of patients aged 70-74, 75-79, 80-84, and ≥ 85 years, respectively, received chemotherapy. Among them, platinum doublets were prescribed for 62.7% of the patients who were aged ≥ 70 years, and 60.7% of the patients who were aged ≥ 75 years with no driver mutations in NSCLC; only 37.6% of them received single agents. Patients who were aged ≥ 80 years also preferred platinum doublets (35.6%). Carboplatin was commonly prescribed in all age groups; only 28.4% of those receiving platinum doublets selected cisplatin. In this study, platinum doublets were identified as the most commonly prescribed regimen in those who were aged ≥ 70 years. Despite recommendations of Japanese guidelines for NSCLC, 60.7% of those who were aged ≥75 years received platinum doublets. Additionally, patients who were aged ≥ 80 years also received systemic chemotherapy, including platinum doublets; age did not solely influence regimen selection.