Fatostatin A is a highly potent, specific and cell permeable inhibitor of Sterol Regulatory Binding Proteins (SREBPs). It inhibits the ER-Golgi translocation of SREBPs via binding to their escort protein (SCAP). It blocks adipogenesis by inhibiting the activation of SREBP-1 and SREBP-2. It exhibits anti-proliferative effects on DU 145 cells independently of IGF-1 signaling (IC50 ~0.1 μM). Fatostatin A can prevent increases in body weight, blood glucose and hepatic fat accumulation and reverses hyperglycemia in diabetic (ob/ob) mice, even under uncontrolled food intake. Fatostatin A may serve as a tool for gaining further insights into the regulation of SREBP.