Lipids are an essential component of cellular bilayer membranes and the major energy reserve in cells and tissues; lipid homeostasis is crucial for normal cell morphology, integrity and function. Apart from adipose tissue, lipids are most abundant in the brain, which contains approximately 60% lipids. Lipids are critical for neuronal development, plasticity, and function. Abnormal lipid metabolism contributes to the pathogenesis of several neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. Some positive clinical outcomes of statins, a class of cholesterol-lowering drugs, in Alzheimer's disease also emphasize lipids as potential therapeutic targets. Currently, it is unclear whether altered lipid homeostasis in neurodegenerative disorders reflects earlier pathological events, or in fact triggers those events. In either case, further understanding of the mechanisms involved will be of great value in developing drugs to either treat or prevent various neurodegenerative disorders.