Normal physiological processes are under control of circadian rhythms. Moreover, certain pathological events, such as cardiovascular accidents (myocardial infarction, stroke) occur more frequently at specific times of the day. Recent observations demonstrate a causal relationship between alterations in circadian rhythmicity and metabolic disorders. Disruption of clock genes results in dyslipidemia, insulin resistance and obesity, all predisposing to atherosclerosis. The nuclear receptor Rev-erbα is part of the clock circuitry and plays an important role in keeping proper timing of the clock. Rev-erbα also regulates lipid metabolism, adipogenesis and vascular inflammation. Interestingly, Rev-erbα also cross-talks with several other nuclear receptors involved in energy homeostasis. Therefore Rev-erbα may serve to couple metabolic and circadian signals.