The treatment of the growth hormone deficient (GHD) adolescent in transition to adulthood remains challenging. Fifty-eight GHD adolescents (mean age: 15.8 ± 1.8 yr, 33 males) who were near completion of their linear growth were studied at baseline while on GH. Subjects were classified as persistently GHD or controls (n = 18) 4w after discontinuing treatment. The GHD group was randomized to GH (n = 25, 20 µg/kg/d) or placebo (n = 15) for 2 yr. All groups had normal measures of lipid and carbohydrate metabolism, body composition, bone mineral density (BMD), cardiac function, muscle strength and quality of life (QOL) at baseline and during 2 yr of follow up. IGF-I concentrations decreased in all subjects, but less so in the GH-treated group (P = 0.013). There was a greater increase in lean body mass (with lesser increase in adiposity) in the GH group than placebo at 12mo, but no differences were observed after 24mo. In conclusion: 1- GHD patients properly treated in childhood can have normal BMD, body composition, cardiac function, muscle strength and measures of carbohydrate and lipid metabolism, as well as measures of QoL when they reach adult height; 2- continuation of GH therapy for 2 yr did not change these measures compared with placebo-treated or control subjects. GHD adolescents in good metabolic status at the time of epiphyseal fusion may safely discontinue GH for at least 2 yr. Careful follow up is needed to determine if GH therapy is eventually warranted in subjects treated with GH during childhood.