A growing body of evidence indicates that exposure to environmental chemicals can contribute to the etiology of obesity by inappropriately stimulating adipogenesis as well as perturbing lipid metabolism and energy balance.One potential mechanism by which chemical exposure can influence lipid metabolism is through disturbance of circadian rhythms,endogenously-driven cycles of roughly 24hr in length that coordinate biochemical,physiological,and behavioral processes in all organisms.Here we show for the first time that exposure to endocrine disrupting compounds (EDCs),including the pesticide tributyltin,two commercial flame retardants,and a UV-filter chemical found in sunscreens,can perturb both circadian clocks and lipid metabolism in vertebrates.Exposure of developing zebrafish to EDCs affects core clock activity and leads to a remarkable increase in lipid accumulation that is reminiscent of the effects observed for longdaysin,a known disruptor of circadian rhythms.Our data reveal a novel obesogenic mechanism of action for environmental chemicals,an observation which warrants further research.Because circadian clocks regulate a wide variety of physiological processes,identification of environmental chemicals capable of perturbing these systems may provide important insights into the development of environmentally-induced metabolic disease.