Growth Hormone deficient (GHD) children who have been treated with human growth hormone (hGH), often complain of weakness and fatigue after discontinuation of therapy. GH deficiency is associated with an increase in subcutaneous fat and a decrease in body muscle mass which means that fat free mass (FFM) diminishes. Also the basal metabolic rate is decreased partially due to decrease of the metabolic activity of the fat free mass. In this study six (GHD) patients were investigated before, 6 and 26 weeks after discontinuation of GH treatment. Body composition was performed by means of under water weighing, deuterium dilution and measurement of skinfold thicknesses. Energy metabolism was measured as sleep metabolic rate (SMR) during an overnight stay in a respiration room and as basal metabolic rate(BMR) measured with a ventilated hood. The patients could be divided in two groups: those who after diagnosis of GHD responded on therapy with an increase in growth velocity and those who did not respond. The responders showed an increase in subcutaneous fat and a decrease in metabolic rate after discontinuation of hGH therapy in contrast to the non-responders.