The actions of growth hormone (GH) are not restricted to growth: GH modulates metabolic pathways as well as neural, reproductive, immune, cardiovascular, and pulmonary physiology. The importance of GH in most physiological systems suggests that GH deficiency at any age would be associated with significant morbidity. However, prior to the advent of recombinant GH, cadaver-derived GH was only used therapeutically to correct the height deficit, and thereby hypothetically improve quality of life (QoL), in GH-deficient children. Physicians now have access to unlimited, albeit expensive, supplies of recombinant GH, and are considering the advisability of GH replacement or supplementation in other patient populations. This paper analyses studies investigating the relationship between GH and QoL in GH-deficient children or adults, in GH-replete short children suffering from idiopathic short stature, Turner syndrome, or intrauterine growth retardation and in GH-deficient or replete elderly adults. Possible mechanisms by which GH might improve QoL at neural and somatic sites are also proposed.