Coenzyme Q10 (CoQ10) is a vitamin-like antioxidant, essential for proper function of mitochondrial respiratory chain. It has been shown that there is a decrease level of CoQ10 in several tissues with aging (like muscle). We suggest that one possible explanation for altered oocyte mitochondrial function may be diminished CoQ10 substrate availability or utilization as a function of aging. The oocytes, and in fact the pre-granulosa cells which give rise to the granulosa (GC) and cumulus cells (CC), are unique in the body since there is no cell division for many years. Therefore, in older women, the oocytes and GCs in primordial follicles will have been exposed to low levels of radical oxygen species produced by mitochondrial respiration over decades, resulting in possible cumulative damage to mitochondria and DNA. Decreased availability of CoQ10 would contribute to reduced antioxidant activity and decreased ATP production by the mitochondria in the oocyte. In addition, compromised mitochondrial function in GCs can effect steroid hormone production, as steroidogenesis is initiated in the inner mitochondrial membrane. Thus, a vicious circle is created by which decreased CoQ10 bioavailability with advanced age could adversely affect meiosis and further developmental competence of gametes.