The availability for clinical use of somatocrinine growth hormone releasing hormone (GRF) brings about the possibility of treatment of growth hormone deficient children (GHD) of hypothalamic origin. We present the results of the first 6 months of treatment of GRF in 20 GHD children. Ten boys and 10 girls with mean chronological age of 10.7 ± 2.7 yr, bone age 6.1 ± 2.5 “yr” and with a mean growth retardation of 4.7 ± 0.6 SD were treated with GRF 1 - 44 SANOFI by daily (N = 11) or thrice weekly (N = 9) subcutaneous injection in doses of 10 ug/kg body weight. All of the children were in prepubertal stage and in all the peak GH response to clonidine and I'dopa provocative tests was below 5 ng/ml. Nine patients had TSH deficiency and were parallely treated with I'thyroxine. The GRF i.v. bolus test was performed before treatment and 2 and 6 months after initiation of treatment. In 9 out of 20 patients acceleration of growth velocity was found. Three patients reached a growth velocity of more than 4.4 cm per yr. Growth velocity during the treatment was significantly correlated with peak GH response to GRF i.v. bolus before (r = 0.6786) and during the treatment (r = 0.4863 and r = 0.5947, respectively). The growth velocity was greater in younger children and in those with less advanced bone age. Acute response to GRF was significantly greater after 6 months of treatment than before the treatment (mean peak GH response 2.9 ± 3.0 and 7.6 ± 8.1 ng/ml respectively, p < 0.05). No side effects of the treatment were observed and immunological tolerance was good. We concluded that chronic administration of GRF is well tolerated and resulted in enhanced growth in some of the GHD children and evoked better response of somatotrophs to GRF i.v. bolus. The GH response to a single i.v. GRF bolus may have a prognostic value for growth response to GRF therapy.