The significance of serum insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein 3 (IGFBP-3) levels in uremia is still controversial. In this study we measured serum IGF-I by immunoradiometric assay (IRMA) and IGFBP-3 levels by specific radioimmunoassay (RIA) in 28 children (aged 3-16 years) with end-stage (n=14, on hemodialysis) and pre-terminal renal failure (n=14) and in 15 age-matched healthy children. Thyroid function of the patients was also investigated and GH-stimulation tests with L-Dopa and insulin were performed. Neither IGF-I nor IGFBP-3 levels significantly correlated with mean height SDS for bone age or for chronological age in either non dialysis patients or pubertal (n=10) or prepubertal patients (n=18). These data was consistent with the concept that growth in CRF was not related to abnormalities in serum IGF-I or IGFBP-3 levels.