For the present, to determine growth hormone(GH) deficiency in patients with short stature, many provocative tests using various pharmacological agents such as glucagon, insulin, clonidine, arginine, growth hormone releasing factor, etc. should be done. These are not only complicated but are also misleading in some patients. In search of a simple and accurate method of detecting GH deficiency that may replace the more complicated provocative tests, we measured basal plasma insulin-like growth factor-I (IGF-I) to see the correlation with the peak GH values in the GH stimulation test. But, in each group of patients with different types of short stature, IGF-I values were poorly correlated. In addition, IGF-I values of the patients with short stature compared to the age- and sex-matched normal ranges showed a significant overlap, and the difference between the proportion of patients with subnormal values in GH deficient patients and non-GH deficient patients was not prominent. Nevertheless, in response to human growth hormone (hGH) administration, both the yearly growth rate and IGF-I levels increased conspicuously. Therefore, even though it may not be feasible to use IGF-I as a single diagnostic measure of patients with short stature, the change in IGF-I values in the follow up of hGH therapy may well represent the response to hGH.