Abstract Background Potentially inappropriate medications (PIM) are medicines for which the risks for adverse events (AEs) usually outweigh the clinical benefits in older adults. PIM is associated with an increased risk of AEs, hospitalizations, mortality and higher health care costs. This analysis presents the prevalence of PIM use and associated factors in people aged 66+ years living in Germany. Methods Data from the nationally representative Study on Health of Older People in Germany (Gesundheit 65+) conducted between 2021-2023 by the Robert Koch Institute, was analyzed. All medicines used, prescribed and over-the-counter (OTC), in the 7 days before the interview were classified into anatomical therapeutic chemical codes. PIM use was identified based on the PRISCUS 2.0 list. Weighted prevalences and associated factors for PIM use are presented. Results 96% of the sample (N = 1,474) took at least 1 medication in the 7 days before the interview. The prevalence of PIM use was 29% (95% CI: 26%-32%), 23% took 1 PIM and 6% 2+. There were no sex differences but a significant increase with age: 23% in the age group 66-74, 33% in the age group 75-84, and 39% in the age group 85 + (29% 1 PIM and 10% 2+). People with a low educational level had a PIM prevalence of 32% compared to 21% in those with a high educational level. Among those reporting having chronic diseases, the PIM prevalence was 34% compared to 19% among those not reporting them. The prevalence of PIM increased with the number of medicines used: 13% in 1-4 medicines, 31% in 5-9 medicines, and 53% in 10+ medicines. The most frequently used PIM in this sample was ginkgo biloba leaf extract (plant-based antidementia drug) followed by diclofenac (non-steroidal anti-inflammatory drug), and then by tricyclic antidepressant drugs (opipramol and amitriptyline). Conclusions PIM use was higher than suggested by prescription data analysis. It was associated with higher age, chronic diseases, polypharmacy and a low educational level. Key messages • PIM use was common, affecting more people with chronic diseases, older age groups and people with a low educational level. • Strategies to promote and monitor appropriate medication use are needed.