AIM: Older adults with cancer are often at increased risk for postoperative complications following major surgeries. This study aimed to evaluate the combined role of frailty and sarcopenia in predicting postoperative complications in older adults with hepatobiliary and pancreatic cancer undergoing surgery. METHODS: This retrospective study included 107 Japanese patients who underwent comprehensive geriatric assessment (CGA) at the geriatric oncology service before cancer treatment decisions and subsequent curative surgery for hepatobiliary and pancreatic cancer. Frailty status was measured using the validated 10-item frailty index based on a CGA (FI-CGA-10) and categorized as fit, prefrail, or frail. Sarcopenia was assessed using bioelectrical impedance analysis and grip strength. The primary outcome was postoperative complications, defined as Clavien-Dindo grade ≥ III, within 1 month of surgery. RESULTS: The median age of the 107 patients was 79 (range, 75-89) years. Patients were categorized as fit ( CONCLUSION: In this study, patients classified as prefrail/frail and sarcopenic were at significantly higher risk for postoperative complications.