Bone remodeling is a complex process regulated by systemic agents and local factors. During the past several years most or perhaps all the growth factors associated with the bone matrix have been characterized, and important information regarding hematologic factors has become available. Growth factors have significant effects on bone remodeling and likely play a major role in the maintenance of normal bone mass, wound healing, and fracture repair (Tables 3 and 4). Current studies indicate that systemic hormones regulate the synthesis and receptor binding of a number of local factors. By these mechanisms, specific hormones may target their effects to the skeleton. Although our knowledge of local growth factors is still limited, future work should determine their role in skeletal physiologic and pathophysiologic conditions and their potential as therapeutic agents.