• We evaluated the effect of growth hormone (GH) therapy on the posttreatment growth of 11 poorly growing children who had normal GH response to provocative stimuli but subnormal integrated concentrations of GH. Patients received 0.1 U/kg of GH three times per Week. Their mean (±SD) growth rate increased from 3.3±1.0 cm/y before treatment to 6.5±1.4 cm/y after eight months of treatment. The growth rates of five patients declined to below 4.5 cm/y four months after treatment. Three of these patients resumed GH therapy and again responded with increased growth velocity (8.0±1.2 cm/y). After therapy, the growth rate of five remaining patients continued to be greater than 4.5 cm/y (6.8±1.4 cm/y). Two of these patients had entered puberty and their posttreatment growth rate might have been due to a pubertal growth spurt. The three prepubertal patients in this group had a gradual decline in growth velocity to 3.8±1.0 cm/y by the end of 12 posttreatment months. We conclude that maintenance of normal growth in patients with this pattern of GH deficiency is dependent on GH replacement therapy.