We report here a case with severe intrauterine growth restriction from the first trimester and clinical features of Silver-Russell syndrome including microcephaly, low-set ear, atrial septum defect, ventricular septum defect, diaphragmatic relaxation, and rocker bottom feet. Silver-Russell syndrome is thought to result from deletion of the distal long arm of chromosome 15 on which the IGF-I receptor (IGF-IR) gene is located. We measured both the maternal and cord blood levels of GH, IGF-I, and IGF-binding protein and performed an immunohistochemical study of IGF-IR in the placenta to investigate whether these IGF-related proteins were affected in this patient. The hormonal level of these proteins did not significantly differ from normal neonates, and immunohistochemical analysis suggested IGF-IR protein levels in the placenta were comparable to normal term neonates. These results support the hypothesis that growth insufficiency could occur in patients with monosomy of the distal long arm of chromosome 15 and suggest a critical threshold for IGF-related fetal growth in early pregnancy.