Background Frailty is an age-related health condition affecting an estimated 18% of older adults in Europe and past evidence has shown a relationship between socioeconomic factors and frailty. We examined population frailty trends and the association between frailty and 5-year mortality by education tertiles and income quartiles at ages 75, 85 and 95 in Swedish registry data. Methods All Swedish residents born in 1895–1945 and in the Total Population Register from 1990 to 2020 were included. Frailty was assessed with the Hospital Frailty Risk Score (HFRS), which sums 109 weighted Internation...