ABSTRACT: OBJECTIVE:This study aimed to estimate the association of frailty with incidence and mortality of fractures at different sites in people aged over 80 years. DESIGN:Cohort study. SETTING:UK family practices from 2001 to 2014. PARTICIPANTS:265?195 registered participants aged 80 years and older. MEASUREMENTS:Frailty status classified into 'fit', 'mild', 'moderate' and 'severe' frailty. Fractures, classified into non-fragility and fragility, including fractures of femur, pelvis, shoulder and upper arm, and forearm/wrist. Incidence of fracture, and mortality within 90 days and 1?year, were estimated. RESULTS:There were 28?643 fractures including: non-fragility fractures, 9101; femur, 12 501; pelvis, 2172; shoulder and upper arm, 4965; and forearm/wrist, 6315. The incidence of each fracture type was higher in women and increased with frailty category (femur, severe frailty compared with 'fit', incidence rate ratio (IRR) 2.4, 95% CI 2.3 to 2.6). Fractures of the femur (95-99 years compared with 80-84 years, IRR 2.7, 95% CI 2.6 to 2.9) and pelvis (IRR 2.9, 95% CI 2.5 to 3.3) were strongly associated with age but non-fragility and forearm fractures were not. Mortality within 90 days was greatest for femur fracture (adjusted HR, compared with forearm fracture 4.3, 95% CI 3.7 to 5.1). Mortality was higher in men and increased with age (HR 5.3, 95% CI 4.3 to 6.5 in those over 100 years compared with 80-84 years) but was less strongly associated with frailty category. Similar associations with fractures were seen at 1-year mortality. CONCLUSIONS:The incidence of fractures at all sites was higher in women and strongly associated with advancing frailty status, while the risk of mortality after a fracture was greater in men and was associated with age rather than frailty category.