Background Current readmission rates do not account for readmissions to nonindex hospitals and may underestimate the actual burden of readmissions. Objective Using a nationally representative database, we sought to characterize nonindex readmissions following bariatric surgery and identify risk factors associated with readmission to a nonindex hospital. Setting Patients in the United States undergoing elective bariatric surgery. Methods The Nationwide Readmissions Database was used to identify a weighted sample of 545,377 patients undergoing elective bariatric surgery between 2010 and 2014. Multivariable logistic regression analysis was used to identify factors associated with readmission to a nonindex hospital. Results Among all patients, 5.6% were readmitted at least once within 30 days. Within the subgroup of patients who were readmitted, 17.6% were readmitted to a different hospital than the index admission hospital. Factors independently associated with higher odds of readmission to a nonindex hospital were primary payor (Medicare: odds ratio [OR] = 1.48, 95% confidence interval [CI]: 1.24–1.75; Medicaid: OR = 1.56, 95% CI: 1.26–1.95), All Patients Refined Diagnosis Related Group severity of illness score (extreme versus minor: OR = 1.48; 95% CI: 1.04–2.09), primary procedure (laparoscopic sleeve gastrectomy versus laparoscopic gastric bypass: OR = 1.23; 95% CI: 1.05–1.44), hospital bed size (reference: small hospital, medium: OR = .52, 95% CI: .39–.70; large: OR = .47, 95% CI: .35–.63), hospital ownership (reference: private, nonprofit hospital, government: OR = 1.77, 95% CI: 1.32–2.37; private, investor-owned: OR = 1.33, 95% CI: 1.07–1.64), and hospital location (reference: metropolitan area >1 million population, metropolitan Conclusion Failure to account for readmissions to different hospitals may underestimate readmission rates by approximately 18%.