The Growth hormone (GH)/IGFI- axis plays a central role in longitudinal bone growth as well as in the acquisition and maintenance of bone mass in children. Studies, in both growth hormone excess and deficiency, suggest that growth hormone may be useful as an anabolic agent in children with osteoporosis. In acromegaly, bone turnover markers indicate activation of both osteoblasts and osteoclasts. Both markers correlate with circulating GH and IGF-1 levels. IGF-1 levels are increased in cortical bone suggesting that the anabolic actions of GH are mediated by local production. The impact on bone density in unclear, as some studies show no differences from healthy controls. However, other studies indicate an increase in cortical bone mass while trabecular mass appears to be unchanged or somewhat reduced. Furthermore rates appear not to be increased.