This study will investigate the safety and efficacy of a new sustained release formulation of recombinant human growth hormone, ProLease hGH. Human growth hormone (hGH) is the most abundant and most extensively studied hormone produced and secreted by the pituitary gland. Because hGH has been available for use in humans for more than 30 years, much is known about its physiology and mechanism of action. GH is essential for sustaining longitudinal skeletal growth and maintaining metabolic balance, mediated by factors induced by GH, particularly insulin-like growth factor. The objective of the Phase I/II study is to demonstrate the safety and efficacy of a new sustained release formulation of growth hormone on the treatment of growth failure in children with GH deficiency.