The aim of this prospective controlled study was to assess the effect of rhGH in short prepubertal children with intrauterine growth retardation and normal growth hormone status. Twenty-six children were randomized into treatment (12F, 4M) and control (6F, 4M) groups. Mean ages were 5.3 (1.3) yr and 4.3 (1.7) yr, respectively. rhGH (Genotropin(R)) was used at a dose of 0.2 IU/kg/day as daily s.c. injections for two years, In the treated group, mean height SDS increased from -3.0 (0.5) to -1.9 (0.7) and height velocity SDS showed a significant increase from -1.3 (2.0) to 3.7 (1.8) in the first year (p < 0.001) and 1.6 (1.8) (p < 0.01) in the second year of treatment. In the controls, height SDS, initially -2.7 (1.4), and height velocity SDS, initially -0.9 (1,1), remained essentially the same during two years of follow-up. Height SDS for bone age changed by 0.6 in the treated group and 0.4 in the control group. Target height SDS - initial height SDS in the treated group improved by 1.1 SD but declined in the control group. IGF-I levels increased from 9.5 (4.2) nmol/l (72 [31.8] ng/ml) to 32.5 (27.0) nmol/l (244.4 [202.8] ng/ml) (p = 0.004) in the treated group while no change was observed in the controls. No adverse effects were encountered during rhGH therapy. It was concluded that rhGH treatment induces a significant increase in growth velocity in the short term. This outcome, as opposed to the unchanged indices in the control group over the same period, may be indicative of an improved height prognosis in short children born with intrauterine growth retardation treated with rhGH.