Outcome after surgery in patients with asthma remains unknown. The purpose of this study is to investigate postoperative major complications and mortality in surgical patients with asthma.Using reimbursement claims from the Taiwan National Health Insurance Research Database, the authors identified 24,109 surgical patients with preoperative asthma and 24,109 nonasthma patients undergoing major surgeries using matching procedure with propensity score by sociodemographics, coexisting medical conditions, and surgical characteristics. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for 30-day postoperative complications and mortality associated with asthma were analyzed in the multivariate logistic regressions.Asthma increased postoperative pneumonia (OR 1.48; 95% CI 1.34-1.64), septicemia (OR 1.11; 95% CI 1.02-1.21), and urinary tract infection (OR 1.17; 95% CI 1.09-1.26). Preoperative emergency care for asthma was significantly associated with postoperative 30-day in-hospital mortality, with an OR of 1.84 (95% CI 1.11-3.04). Preoperative emergency service, hospitalizations, admission to intensive care unit, and systemic use of corticosteroids for asthma were also associated with higher postoperative complication rates for asthmatic patients.Postoperative complications and mortality were significantly increased in asthmatic patients. We suggest urgent efforts to revise protocols for asthma patients' perioperative care.