BACKGROUND: The retinoblastoma protein (pRB) and p53 are crucial members of regulatory networks controlling the cell cycle and apoptosis, and a hallmark of virtually all cancers is dysregulation of expression or function of pRB or p53. Although they are best known for their role in cancer development, it is now evident that both are implicated in metabolism and cellular development. OBJECTIVE/METHODS: To review the role of pRB and p53 in adipocyte differentiation and function emphasizing that pRB and p53, via their effects on adipocyte development and function, play a role in the regulation of energy metabolism and homeostasis. RESULTS/CONCLUSIONS: pRB is required for adipose conversion and also involved in determining its mitochondrial capacity. p53 inhibits adipogenesis and results suggest that it is involved in maintaining function of adipose tissue.