Nine stunted prepubertal children with end-stage renal failure were treated by rhGH in supraphysiological doses (4 U/m2/day s.c.) for a period of six to nine months. The six-month data from these children indicated that exogenous rhGH significantly improved the growth rate in all children (mean height velocity SDS before therapy, -2.8; during the treatment period, +2.5). This effect was accompanied by a significant increase in serum somatomedin bioactivity. Low normal basal serum IGF I concentrations were increased by rhGH. Elevated basal serum IGF II concentrations were further increased by rhGH treatment. The pharmacokinetic profile of rhGH in uremia resembles that of the non-uremic state; no accumulation was seen after 14 days of treatment. Glucose tolerance did not change, and insulin levels remained stable throughout the six-month observation period. No rhGH antibodies were detected. Although these short-term results are very encouraging, the effects of rhGH on the prognosis for final height need to be assessed over a longer period of time.