Insulin-like growth factor (IGF)-binding protein-2 (IGFBP-2) is altered in different diseases and might be used as an indication of its severity. The aims of our study were to investigate: (1) the developmental pattern of the serum IGFBP-2 concentration at birth and during childhood and adolescence; (2) whether the serum IGFBP-2 level could be a marker for the diagnosis and evolution of diseases where the growth hormone (GH)-IGF axis is altered, and (3) whether this binding protein shows a relationship with IGF-I, its free fraction, IGFBP-1 and -3. We report reference values for 55 normal full-term newborns and 221 normal children who were divided into 5 groups according to their Tanner stage. Serum levels were higher in newborns when compared with Tanner stages I–V (p < 0.001, ANOVA), with no further changes throughout development. Furthermore, we studied IGFBP-2 levels in 24 children with congenital GH deficiency (GHD), 26 with acute lymphoblastic leukemia (ALL), 75 obese children, and 60 girls with anorexia nervosa (AN) at diagnosis and during a follow-up period. IGFBP-2 at diagnosis was increased in GHD, ALL and AN, and decreased in obesity (p < 0.05, ANOVA). During the follow-up, IGFBP-2 concentrations tended to normalize. IGFBP-2 correlated positively with IGFBP-1 and negatively with IGF-I and IGFBP-3 in normal subjects and at diagnosis of the pathologies studied. Although IGFBP-2 functions are not well understood, these results suggest a possible role for this protein in diseases where the GH-IGF axis is altered.