In-patient comprehensive geriatric assessment (CGA) may reduce short-term mortality, increase the chances of living at home at 1 year and improve physical and cognitive function. We systematically reviewed the literature and found 20 randomized controlled trials (10 427 participants) of in-patient CGA for a mixed elderly population. This includes seven more recent randomized controlled trials that update a previous review. Newer data confirm the benefit of in-patient CGA, increasing the chance of patients living at home in the long term. Overall, for every 100 patients undergoing CGA, three more will be alive and in their own homes compared with usual care [95% confidence interval (CI) 1-6]. Most of the benefit was seen for ward-based management units (four patients per 100 treated, 95% CI 1-7) with little contribution from team-based care (no patients per 100, 95% CI -4 to +5). However, CGA does not reduce long-term mortality. This evidence should inform future service developments.