We and other have recently shown that growth differentiation factor 15 (GDF15) is a useful diagnostic marker for mitochondrial diseases, which are inherited disorders caused by mitochondrial or nuclear genomic mutations that lead to impaired energy production. As the primary cause of mitochondrial diseases is mitochondrial dysfunction, the blood level of GDF15 might reflect mitochondrial function in patients, and thus could be a marker for mitochondrial dysfunction. GDF15 has been implicated in aging and various age‐related disorders, such as cardiovascular diseases and diabetes, the blood level of which is reportedly elevated in older adults as well as in patients. Although GDF15 might be induced as a result of various cellular stresses and dysfunctions, it would also be possible that the blood GDF15 level reflects at least in part mitochondrial dysfunction in aging and age‐related disorders. In the present review, we summarized the current literature regarding GDF15 in aging and age‐related disorders from the perspective of biomarkers, with a particular focus on mitochondrial dysfunction. Geriatr Gerontol Int 2016; 16 (Suppl. 1): 17–29.