There is an accumulating body of evidence in the literature suggesting that testosterone may be neuroprotective and therefore have therapeutic value in the treatment of neurodegenerative diseases. In this article, the potential mechanisms of action of testosterone on the central nervous system are discussed, as well as the current evidence supporting the effect of testosterone on neurological impairment. Lower endogenous testosterone levels appear to be associated with some neurological disabilities. Conversely, a therapeutic benefit of exogenous testosterone supplementation on some cognitive abilities has been shown in pilot trials involving healthy elderly men as well as patients with multiple sclerosis and Alzheimer's disease. Further study of the therapeutic potential of testosterone is warranted in neurological and neuropsychiatric diseases.