Children with Prader-Willi syndrome (PWS) who receive GH treatment have improved growth and body composition; however, data are lacking for adults when treatment is discontinued after completion of growth. Our aim was to compare body composition and metabolic status in adults with PWS according to GH treatment in childhood and adolescence. 64 adults (mean age: 25.4 years) with a genetic diagnosis of PWS were evaluated: 20 received GH in childhood (T), which had been discontinued at the time of this study, and 44 did not receive GH (C). Mean duration of treatment in the T group was 4.4 ± 2.7 years, age at baseline was 11.8 ± 2.7 years, mean time between the end of treatment and the current evaluation was 7.0 ± 4.4 years. Dual-energy X-ray absorptiometry was used to assess body composition and fasting biological analyses evaluated metabolic status. RESULTS (MEAN ± SD): Body mass index and percentage of fat mass were significantly lower in the T group (32.4 ± 10.3 vs 41.2 ± 11.1 kg/m(2), P = 0.05 and 44.0 ± 9.6 vs 50.1 ± 7.2%, P = 0.02, respectively). Insulinemia and HOMA-IR in non-diabetic subjects were significantly lower in the T group (5.8 ± 5.9 vs 13.9 ± 11.6 μUI/ml, P = 0.03, and 1.6 ± 1.3 vs 2.7 ± 2.1, P = 0.04, respectively). Non-diabetic and diabetic subjects from the T group had a significantly lower HbA1c. Lipid profiles were similar between groups. GH treatment in childhood and adolescence is associated with significantly decreased body mass index and improved body composition and metabolic status in adults with PWS at several years after discontinuing treatment.