The approval of GH treatment of adults with GH deficiency (GHD) raises issues regarding continuation of GH treatment in the GH-deficient child following achievement of near adult height. The transition period begins in late puberty and ends with full adult maturation and includes hormonal and many lifestyle changes. Children treated with GH should be retested near the time of reaching adult height to determine if they have persistence of GHD. Although most children with organic causes of GHD will again be found to have GHD on retesting, most of those with idiopathic GHD will not. Retesting usually involves measurement of IGF-I and stimulation with insulin-induced hypoglycemia or arginine-GHRH, but important questions remain about adjustment of established cut-offs for age and body mass index. Most studies have shown the benefit of GH treatment in young adults with GHD in body composition, especially the achievement of peak bone mass. It is important for pediatric endocrinologists to discuss the potential need for continued treatment beyond achievement of adult height at the time of initiation of GH treatment, especially in those children with organic causes of GHD.