This article reports the efficacy and safety of treatment with Somatonorm in 9 children with idiopathic growth hormone (GH) deficiency in China. The growth velocity increased from 2.6 +/- 0.2 cm/year before treatment to 10.7 +/- 0.5 cm/year at the end of 1-year treatment. The increment of human growth hormone (hGH) level and area under the response curve above the baseline level were larger after one injection of Somatonorm at the dose of 0.1 IU/kg sc than that of 0.17 IU/kg im. Increments of delayed bone age were not significant. There was no correlation between the increase of height growth velocities and the serum Somatomedin-C (SMC) levels during hGH therapy (r = -0.055). Blood sugar levels and blood alkaline phosphatase concentrations increased significantly after therapy. There were no significant side effects. Serum T4 levels of 3 patients dropped below normal after treatment. Serum anti-hGH antibody appeared at 3-12 month in 2 patients, but it did not attenuate the growth velocity.