This review evaluates the effectiveness and resource use of comprehensive geriatric assessment (CGA) for older adults admitted to hospitals. CGA is a multidimensional, multidisciplinary process aimed at identifying and managing medical, functional, mental, and social issues in older patients. The review includes 29 randomized trials involving 13,766 participants from nine countries. The main findings are: 1. **Living at Home**: CGA increases the likelihood that older adults will be alive and living at home at both discharge and 3 to 12 months follow-up (high-certainty evidence). 2. **Mortality**: CGA does not significantly affect mortality at discharge or 3 to 12 months follow-up (high-certainty evidence). 3. **Admission to Nursing Home**: CGA decreases the likelihood of patients being admitted to a nursing home at discharge and 3 to 12 months follow-up (high-certainty evidence). 4. **Dependence**: CGA has little or no effect on dependence in daily activities (high-certainty evidence). 5. **Cognitive Function**: The impact of CGA on cognitive function is uncertain due to low-certainty evidence. 6. **Length of Stay**: There is a slight increase in mean length of stay in the CGA group compared to the control group (low-certainty evidence). 7. **Costs and Cost-Effectiveness**: CGA may lead to a slight increase in quality-adjusted life years (QALYs), life years (LYs), and life years living at home (LYLAHs), but the cost-effectiveness is uncertain due to low-certainty evidence. The review concludes that CGA is beneficial in improving outcomes for older adults admitted to hospitals, particularly in maintaining their independence and quality of life. However, further research is needed to better understand the cost-effectiveness of CGA and to address the uncertainty in the evidence.This review evaluates the effectiveness and resource use of comprehensive geriatric assessment (CGA) for older adults admitted to hospitals. CGA is a multidimensional, multidisciplinary process aimed at identifying and managing medical, functional, mental, and social issues in older patients. The review includes 29 randomized trials involving 13,766 participants from nine countries. The main findings are: 1. **Living at Home**: CGA increases the likelihood that older adults will be alive and living at home at both discharge and 3 to 12 months follow-up (high-certainty evidence). 2. **Mortality**: CGA does not significantly affect mortality at discharge or 3 to 12 months follow-up (high-certainty evidence). 3. **Admission to Nursing Home**: CGA decreases the likelihood of patients being admitted to a nursing home at discharge and 3 to 12 months follow-up (high-certainty evidence). 4. **Dependence**: CGA has little or no effect on dependence in daily activities (high-certainty evidence). 5. **Cognitive Function**: The impact of CGA on cognitive function is uncertain due to low-certainty evidence. 6. **Length of Stay**: There is a slight increase in mean length of stay in the CGA group compared to the control group (low-certainty evidence). 7. **Costs and Cost-Effectiveness**: CGA may lead to a slight increase in quality-adjusted life years (QALYs), life years (LYs), and life years living at home (LYLAHs), but the cost-effectiveness is uncertain due to low-certainty evidence. The review concludes that CGA is beneficial in improving outcomes for older adults admitted to hospitals, particularly in maintaining their independence and quality of life. However, further research is needed to better understand the cost-effectiveness of CGA and to address the uncertainty in the evidence.