BACKGROUND: As the global population ages and older patients undergo surgery, understanding the association between frailty and postoperative outcomes is crucial to informed decision-making and patient care. There is a lack of research assessing the association between frailty and long-term outcomes in patients admitted to ICUs after surgery. METHODS: We conducted a multicentre retrospective cohort study using Australian and New Zealand Intensive Care Society Adult Patient Database, linked with the Australian National Death Index. Adults aged ≥16 yr admitted to the 175 ICUs in Australia between January 1, 2018, and March 31, 2022, after surgery were included. We excluded patients with cancer or admission to ICU for palliation or organ donation purpose. Patients with Clinical Frailty Scale score 5-8 were considered frail. The primary outcome was survival time up to 4 yr after ICU admission. Survival analysis was performed using mixed-effects Cox regression models and adjusted for age, sex, comorbidities, acute illness severity, and hospital types. RESULTS: We included 216 922 patients of whom 30 860 (14.2%) were frail. Patients with frailty had shorter overall survival time (median [IQR]: 16 [6-29] vs 21 [10-34] months; P<0.01) when compared with patients without frailty. After adjusting for confounders, frailty was associated with a shorter time to death (HR: 2.33, 95% CI: 2.26-2.40). This association was consistent across sensitivity analyses and subgroups. Of note, this association between frailty and shorter time to death was more pronounced in patients aged <65 yr, those undergoing elective surgery, and those without treatment limitations. CONCLUSIONS: In this multicentre study, frailty was associated with shorter time to death amongst postoperative ICU patients without cancer. The association was concordant across all subgroups.