Periampullary cancer has a poor prognosis. Surgical resection is a potentially curative but high-risk treatment. Comprehensive geriatric assessment (CGA) can inform treatment decisions, but has not yet been evaluated in older patients eligible for pancreatic surgery. This prospective observational study included patients ≥ 70 years of age eligible for pancreatic surgery. Frailty was defined as impairment in at least two of five domains: somatic, psychological, functional, nutritional, and social. Outcomes included postoperative complications, functional decline, and mortality. Of the 88 patients included, 87 had a complete CGA. Sixty-five patients (75%) were frail and 22 (25%) were non-frail. Frail patients were more likely to receive nonsurgical treatment (43.1% vs. 9.1% p = 0.004). Fifty-seven patients underwent surgery, of which 52 (59%) underwent pancreaticoduodenectomy. The incidence of postoperative delirium was three times higher in frail patients (29.7% vs. 0%, p = 0.005). The risk of mortality was three times higher in frail patients (HR: 3.36, 95% CI: 1.43-7.89, p = 0.006). Frailty is common in older patients eligible for pancreatic surgery and is associated with treatment decision, a higher incidence of delirium and a three times higher risk of all-cause mortality. CGA can contribute to shared decision-making and optimize perioperative care in older patients.