Forkhead Box O (FoxO) transcription factors play an important role in modulating metabolic functions. FoxOs, which are conserved beyond species and regulated by insulin signaling pathway, are usually expressed in insulin-sensitive tissues, such as liver, pancreas, skeletal muscle and gastrointestinal tract. In calorie restriction or starvation, FoxOs are present in nucleus of cells. They active transcription, increase hepatic gluconeogenesis, decrease insulin secretion, increase feed intake and cause degradation of skeletal muscle for supplying substrates of gluconeogenesis. While in the case of insulin resistance or excessive calorie intake, FoxOs are activated and lose the transcription activity. Also, FoxOs regulate the development of insulin-sensitive tissues by controlling cell differentiation, proliferation, and survival. In this paper, the metabolism and cell cycle related genes controlled by FoxOs in insulin-sensitive tissues and the consequently metabolic effects were reviewed. Further clarification of the function and mechanism of FoxOs in insulin-sensitive tissues will strengthen our understanding about tissues development and energy metabolism.［Chinese Journal of Animal Nutrition, 2010，22（4）:811-816］