Background: the ageing demographic means that increasing numbers of older people will be attending emergency departments (EDs). Little previous research has focused on the needs of older people in ED and there have been no evaluations of comprehensive geriatric assessment (CGA) embedded within the ED setting.Methods: a pre-post cohort study of the impact of embedding CGA within a large ED in the East Midlands, UK. The primary outcome was admission avoidance from the ED, with readmissions, length of stay and bed-day use as secondary outcomes.Results: attendances to ED increased in older people over the study period, whereas the ED conversion rate fell from 69.6 to 61.2% in people aged 85+, and readmission rates in this group fell from 26.0% at 90 days to 19.9%. In-patient bed-day use increased slightly, as did the mean length of stay.Discussion: it is possible to embed CGA within EDs, which is associated with improvements in operational outcomes.