Study objectiveTo determine whether obesity status is associated with perioperative complications, discharge outcomes and hospital length of stay in older surgical patients. DesignSecondary analysis of five independent study cohorts (N = 1262). SettingAn academic medical center between 2001 and 2017 in the United States. PatientsPatients aged 65 years or older who were scheduled to undergo elective spine, knee, or hip surgery with an expected hospital stay of at least 2 days. MeasurementsBody mass index (BMI) was stratified as nonobese (BMI ≤ 30 kg/m2), obesity class 1 (30 kg/m2 ≤ BMI < 35 kg/m2) or obesity class 2–3 (BMI ≥ 35 kg/m2). Primary outcomes included predefined intraoperative and postoperative complications, hospital length of stay (LOS), and discharge location. Univariate and multivariate logistic regression was performed. Main resultsObesity status was not associated with intraoperative adverse events. However, obesity class 2–3 significantly increased the risk for postoperative complications (IRR 1.43, 95% CI 1.03–1.95, P = 0.03), hospital LOS (IRR 1.13, 95% CI 1.02–1.25, P = 0.02) and non-home discharge destination (OR 1.95, 95% CI 1.35–2.81, P < 0.001) after accounting for patient related factors and surgery type. ConclusionsObesity class 2–3 status has prognostic value in predicting an increased incidence of postoperative complications, increased hospital LOS, and non-home discharge location. These results have important clinical implications for preoperative informed consent and provide areas to target for care improvement for the older obese individual.