There is increasing evidence that impairment of mitochondrial function and oxidative damage are contributing factors to the pathophysiology of Parkinson's disease (PD). Studies have reported decreased levels of the mitochondrial electron transport chain carrier, coenzyme Q(10) (CoQ(10)) in plasma and platelets from PD patients. Although a deficit in peripheral CoQ(10) has been reported no studies have assessed the CoQ(10) status of the PD brain. In this study we investigated the CoQ(10) status of the substantia nigra, cerebellum, cortex and striatum brain regions of both PD patients and age-matched controls. The results of this study indicate a significant reduction (p=0.007) in CoQ(10) concentration in the cortex region of the brain. In conclusion, the results of this study indicate evidence of a deficit in brain CoQ(10) status may be involved in the pathophysiology of PD.