Forty-two children, aged 2-21.5 years on hemodialysis with a height below -2.0 standard deviation score (SDS) for age, were selected to receive recombinant human growth hormone (rhGH) therapy at 17 French centers. Of the 42 children, 36 were prepubertal and 8 were in early puberty (testicular volume between 4 and 8 ml for boys, breast development B2 or B3 in girls). All received 1 IU/kg per week by daily subcutaneous injection for 1-5 years. The year before rhGH therapy served as a control period. During the 1st year of treatment, mean growth velocity increased from 3.5 to 7.0 cm/year (P < 0.0001) and was always over 2.5 cm/year. This velocity allowed a catch-up growth of +0.5 height SDS. Neither weight nor the body mass index varied compared with the pretreatment year. No change was observed in urea, creatinine, or glucose tolerance. The mean increment in bone age was 0.9 years. The mean growth velocity decreased over subsequent years (P < 0.0001), but remained higher than the prestudy velocity. A significant negative correlation was observed during the 1st year between the increase in growth velocity and the prestudy velocity (P < 0.0001), with the least gain in patients who had the best spontaneous velocity. Pubertal status had no influence on response to rhGH. No significant side effects were observed during the 103 treatment-years. Five patients developed secondary hyperparathyroidism and 1 suffered from acute pancreatitis, but the relationship with rhGH therapy remains uncertain. rhGH therapy appears indicated for children on hemodialysis, even though the potential benefits appear somewhat lower for those with a spontaneous growth velocity over 6 cm/year.