Objective In the last five years significant progress has been made in defining the role of insulin like growth factors (IGFs) in the process of bone remodeling.In this paper,we present critical evidence that IGF-Ⅰ and IGF Ⅱ are produced by bone cells and regulate specific osteoclastic functions.In addition,we review work from several labora tories establishing the role of the skeletal IGF binding proteins as an integral component of a unique IGF regulatory system.According to related evidences,the bone remodeling process may exert their effects through the IGF regulatory system.In contrast to the well-defined local action of IGF-Ⅰ and IGF-Ⅱ on the skeleton,the relationship between circulating IGF-Ⅰand bone remodeling is less certain.Newer research results show that the potential utility of serum growth factor measure ments have certain effects in clinical states.Finally,this paper presents an overview of the most current efforts to stimulate bone formation using recombinant IGFs.However,work on the beneficial aspects of IGFs for the skeleton remains prelimi nary at best with the eventual therapeutic role of IGF-Ⅰ in osteoporosis yet to be defined. Key words: Osteoporosis; Bone mineral density (BMD); Insulin-like growth factor (IGF); Tumour necrosis factor (TNF)