The growth-promoting effect of recombinant human growth hormone (GH) in children with chronic renal failure was assessed in eight clinical trials. A total of 103 prepubertal children participated in the trials, 34 of whom were undergoing dialysis. The children were treated with GH, 30 IU/m2/week (approximately 1 IU/kg/week), for up to 2 years, and various growth parameters, bone age and renal function were assessed before and during treatment. In all trials, the children showed clear catch-up growth and an improved height SDS after treatment with GH, although the increase in height was less in dialysis patients than in those not receiving dialysis. GH maintained its growth-promoting effect during the second year of treatment; the effect, however, was less marked than during the first year of treatment. Bone age appeared to advance in parallel with chronological age. Median serum creatinine increased from 204 mumol/l to 230 and 262 mumol/l after 12 and 24 months of treatment, respectively, due to increased muscle mass and/or progression of the underlying renal disease. The loss of estimated glomerular filtration rate/year was not different before and during GH treatment.