Comprehensive geriatric assessment is an established clinical approach. It reduces mortality and improves the physical wellbeing of older people in the community or hospitalised for medical reasons. Pre-operative comprehensive geriatric assessment seems a plausible method for reducing adverse postoperative outcomes. The objectives of this systematic review and narrative synthesis are to describe how pre-operative comprehensive geriatric assessment has been used in surgical patients and to examine the impact of comprehensive geriatric assessment on postoperative outcomes in older patients undergoing scheduled surgery. We searched MEDLINE, EMBASE and Web of Science from 1980 to 2013 (week 26). We included five studies: two randomised controlled trials and three before-and-after intervention quasi-experimental studies. Patient populations, interventions and outcome measures varied between studies. Both the randomised trials showed benefit on postoperative outcomes, including medical complications. Two of the before-and-after studies reported a positive impact on postoperative length of stay and other outcomes. The heterogeneity of study methods, populations, interventions and outcomes precluded meta-analysis. Based on this narrative synthesis, pre-operative comprehensive geriatric assessment is likely to have a positive impact on postoperative outcomes in older patients undergoing elective surgery, but further definitive research is required. Clinical services providing pre-operative comprehensive geriatric assessment for older surgical patients should be considered.