Purpose Elderly patients are vulnerable to malnutrition and we have started systematic screening for preoperative malnutrition risk in our institution. This study aims to determine the prevalence and risk factors of preoperative malnutrition risk among elderly surgical patients, and its impact on surgical outcomes. Methods In this retrospective cohort study of patients C 65 yr old undergoing elective surgery, we recorded demographics, medications, preoperative effort tolerance, Malnutrition Universal Screening Tool (MUST) score, American Society of Anesthesiologists physical status (ASA), Charlson Comorbidity Index (CCI), and Edmonton Frailty Score (EFS). Postoperative complications based on This article is accompanied by an editorial. Please see Can J Anesth 2021; this issue.