Growth hormone (GH) is a crucial factor in the build-up and in the maintenance of peak bone mass. Children with GH deficiency have osteopenia and a concomitant reduction in bone turnover. On the other hand, GH therapy improves bone mineral density and stimulates bone turnover. These data suggest that GH treatment may have a beneficial effect on peak bone mass. In children with GH deficiency, the values of some biochemical markers of bone turnover may be closely related to growth response during GH therapy. However, further studies are needed to define the usefulness of bone markers in order to optimize the treatment and to predict the growth outcome in GH-treated children.