The last decade has witnessed a profound resurgence in brown adipose tissue (BAT) research. The need for such a dramatic increase stems from the ever-growing trend toward global obesity. Indeed, it is currently estimated that rates of obesity in developed countries such as the United States exceed 35% of the population (1). The higher incidence of obesity is associated with increased prevalence of the metabolic syndrome including diabetes, hypertension, and coronary heart disease, among others (1, 2). BAT holds great promise in combating obesity given its unprecedented metabolic capacity. Leading the way has been recent studies, which conclusively demonstrate significant quantities of functional BAT in adult humans (3-7). These findings have been complimented by elegant studies elucidating the developmental origin of the brown adipocyte and the transcriptional regulation involved in its differentiation. This review will attempt to meld the wealth of new information regarding BAT development with established literature to provide an up to date synopsis of what is known and thus a framework for future research directions.