Objective: The influence of growth hormone (GH) replacement on patient-reported outcomes (i.e., quality of life, health status and well-being) and cognitive functioning in GH-deficient adults is controversial. Design: We carried out a meta-analysis of clinical trials concerning the influence of GH substitution on patient-reported outcomes and cognitive functions (studies were selected from 1985 to 2004). The results of individual studies were combined in a series of meta-analyses using a random effects model. Effects of GH replacement in GH-deficient adults were compared to baseline and/or placebo. Results: Fifteen studies on GH and patient-reported outcomes were included (830 patients, follow-up 3-50 months). Four of these studies also provided data on cognitive functions (85 patients, follow-up 6-12 months). Relative to baseline, GH treatment is found to have a large effect on patient-reported outcomes at 3 months, a medium effect at 6 months and a small effect at 12 months. With respect to the median treatment duration of 6 months placebo appears to be as effective as GH substitution. Cognitive functioning does not improve after 6 months of GH substitution, relative to baseline. Conclusion: This meta-analysis provides no evidence that GH improves patient-reported outcomes in GH-deficient patients. As the amount of cognitive data was too limited to allow for comparisons with placebo, from the present meta-analysis no conclusions can be drawn with respect to the impact of GH treatment on cognition. © 2004 Elsevier Ltd. All rights reserved.