Diagnostic and therapeutic advances in growth hormone insensitivity (GHI) have occurred principally in two areas: the molecular characterization of patients with GHI and treatment with recombinant human insulin like growth factor-I (IGF-I). This article discusses the current status of molecular diagnosis across the spectrum of the disorder. Treatment with recombinant human IGF-I in classical cases is summarized, and potential new targets for treatment are discussed together with the potential for therapy using the newly developed compound recombinant human IGF-I/IGF binding protein-3.