The morbidity associated with GH deficiency (GHD) in adults is now well established. Furthermore, many controlled clinical trials have demonstrated the efficacy of GH replacement therapy. The aim of the present study was to determine whether the effects of GH replacement in adults are reflected in a reduced use of healthcare resources, in addition to improving quality of life (QoL). Data concerning visits to the doctor, number of days in hospital, and amount of sick leave were obtained from patients included in KIMS (Pharmacia International Metabolic Database), a large pharmacoepidemiological survey of hypopituitary adults with GHD, for 6 months before GH treatment and for 6-12 months after the start of treatment. Assistance required with normal daily activities was recorded at baseline and after 12 months of GH therapy. QoL (assessed using a disease-specific questionnaire, QoL-Assessment of GHD in Adults) and satisfaction with physical activity during leisure time were also assessed. For the total group (n = 304), visits to the doctor, number of days in hospital, and amount of sick leave decreased significantly (P < 0.05) after 12 months of GH therapy. Patients also needed less assistance with daily activities, although this was significant (P < 0.01) only for the men. QoL improved after 12 months of GH treatment (P < 0.001), and both the amount of physical activity and the patients' satisfaction with their level of physical activity improved after 12 months (P < 0.001). In conclusion, GH replacement therapy, in previously untreated adults with GHD, produces significant decreases in the use of healthcare resources, which are correlated with improvements in QoL.