The growth hormone (GH)-IGF-I axis is essential for normal foetal and childhood growth. Defects at different sites in the axis frequently result in short stature which may compromise adult height. We describe a continuum of clinically relevant abnormalities from GH deficiency through to GH resistance and discuss the implementation and interpretation of investigations. We consider appropriate therapy for patients with abnormal auxology and subnormal adult height prognosis, highlighting new data to clarify therapeutic choices leading to optimal clinical outcome.