In this review paper, three pieces of clinical information in childhood are presented: (1) IGFBP-3 may replace GH provocation tests in the diagnosis of GH deficiency (GHD); (2) IGFBP-3 levels are regulated by IGF-I levels in a short period, and (3) ratio of free IGF-I to total IGF-I is high in serum of early infancy, similarly to serum of pregnancy, only partially owing to the presence of IGFBP-3 proteolytic activity. Each paper will be published soon.