The effect of 1-2 years of growth hormone (GH) treatment (28-30 IU/m2/week) on growth rate, bone age, renal function and metabolic parameters was studied in 61 short, slowly growing children with chronic renal disease (20 with preterminal chronic renal failure (CRF), 24 with end-stage renal failure (ESRF) and 17 with functioning renal transplants). Height velocity (2-year data) significantly increased in children with preterminal CRF from a baseline median of 4.1 cm/year to 9.2 cm/year after 1 year and to 6.6 cm/year after 2 years of treatment. In patients with transplants, the corresponding values were 2.6 cm/year before GH treatment and 8.6 and 7.2 cm/year after 1 and 2 years, respectively. This resulted in normalization of height in 8 of the 16 children who completed 2 years of treatment. The growth response after 1 year in children with preterminal CRF was significantly higher than that in children with ESRF. Bone maturation was in proportion to the increase in chronological age; the expected final height of the children therefore increased by approximately 8-10 cm. In children with preterminal CRF, the decrease in glomerular filtration rate was not affected by 2 years of treatment with GH. The incidence of acute rejection in children with transplants was low; however, a slight stimulatory effect of GH could not be excluded. The major metabolic change induced by exogenous GH was an increase in serum levels of insulin in the three treatment groups, though all glucose tolerance tests remained stable over the 2-year period.