Mitochondria have been linked to both necrotic and apoptotic cell death, which are thought to have a major role in the pathogenesis of neurodegenerative diseases. Recent evidence shows that nuclear gene defects affecting mitochondrial function have a role in the pathogenesis of Friedreich's ataxia, Wilson's disease and hereditary spastic paraplegia. There is also accumulating evidence that mitochondrial dysfunction might have a role in the pathogenesis of amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease and Alzheimer's disease. If this is so, a number of therapeutic targets are implicated that might result in novel treatments for neurodegenerative diseases.