Abstract: Background: To review the humanistic and economic burden of generalized anxiety disorder (GAD).Methods: MEDLINE, EMBASE and the Cochrane Library, limited to articles published in English, between 1987 and 2010, in North America, Europe and Australia. The key focus was humanistic or functional outcomes, cost of illness and economic outcomes. Ninety articles fitting criteria on (a) GAD study population, (b) United States, Europe or Australia, and (c) humanistic burden or economic burden were reviewed. Methods and findings were summarized by two researchers; inconsistencies were resolved by a third reviewer.Results: GAD was associated with increased impairments in psychosocial functioning, role functioning, work productivity and health-related quality of life (HRQL). The HRQL impairments were comparable with those associated with depression or panic disorder. Patients with GAD and co-morbid depression reported significantly greater impairment in HRQL than did those with either disorder alone. GAD patients had significantly higher median medical costs than primary care patients without GAD (US $2375 versus $1448). The mean annual medical cost of GAD was $2138 higher than for other anxiety disorders (mean $6475). Finally, GAD was frequently under-recognized in primary care, and available studies reported that only 20% to 32% of patients were adequately treated.Limitations: The review was limited to pharmacologic treatments for GAD and to publications in English.Conclusions: GAD is associated with significant burden on patient functioning and well-being, leading to increased health care utilization and medical costs. Patients with GAD are often suboptimally treated, which adds to the HRQL burden of this disorder.