Depression imposes significant costs on sufferers, their families and care-givers, employers and insurance payers. This article summarises medical and health economics literature regarding the societal economic burden of depression and the incremental economic burden of depression sufferers in comparison with non-depressed counterparts. This substantial knowledge base probably underestimates the true economic burden of the disease because the available data and analysis techniques do not capture all of the subtle costs of this condition. Future investigation is likely to focus on the relationship between depression and comorbid conditions, the role of caregiver burdens, and the economic differences in life outcomes.