PURPOSE: The use of growth hormone (GH) to promote growth in normal short children without classical GH deficiency is controversial. Numerous foreign studies have shown the effects of GH therapy in children with idiopathic short stature (ISS) whereas few has been interested in Korea. Therefore, this study is designed to investigate the effects of GH therapy on ISS by observing correlations and changes among various growth parameters such as, insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3). METHODS: This study was conducted retrospectively with 15 children with ISS in Chungbuk National University Hospital in Korea. Mean age was 11.44+/-2.81 and the children were treated with 0.66 IU/kg/wk dosage of GH for 1 or 2 years. Also, the growth parameters before and after the GH therapy were observed. RESULTS: Height standard deviation score (HT-SDS) was increased from -1.85+/-0.70 to -1.58+/-0.56 at 1 year and to -1.21+/-0.37 at 2 years after GH therapy. Predicted adult height standard deviation score (PAH-SDS) was also increased from -2.10+/-0.52 to -1.67+/-0.59 at 1 year, and to -0.96+/-0.60 at 2 years. Serum IGF-I and IGFBP-3 levels were significantly increased after 1 year and marginally increased after 2 years of GH therapy. CONCLUSION: It is concluded that GH therapy has growth promoting effect. The significant increase in IGF-I and IGFBP-3 levels during the GH therapy suggests that IGF-I and IGFBP-3 are useful predictors of response to the use of GH therapy. It is expected that larger patient samples would provide more reliable information about the effect of GH therapy.