OBJECTIVE Readmission rates after vascular surgery are among the highest within surgical specialties, and lower extremity bypass has the highest readmission rate of vascular surgery procedures. We analyzed how 30-day readmissions and risk factors for readmissions vary by indication for lower extremity bypass. METHODS We queried the 2012-2014 American College of Surgeons National Surgical Quality Improvement Program procedure-targeted vascular cohort to identify all patients who underwent lower extremity bypass. Emergent procedures and planned readmissions were excluded. Patients were stratified by surgical indication: claudication, critical limb ischemia rest pain (CLI RP), critical limb ischemia tissue loss (CLI TL), and other. The χ2 and Wilcoxon rank sum tests were used to test the differences between categorical and continuous variables, respectively. Logistic regression was used to estimate odds ratios for predictors of readmission adjusted for preoperative factors that were selected a priori. RESULTS The overall 30-day readmission rate among the 6112 patients who underwent lower extremity bypass was 14.8%. Readmission rates varied significantly on the basis of the indication for surgery. In unadjusted comparisons, 18.8% of patients with CLI TL were readmitted compared with 16.5% with CLI RP, 9.4% with claudication, and 8.2% with other indications (P < .001). After adjustment for preoperative factors, 30-day readmissions were higher for patients with CLI TL (odds ratio, 1.67; 95% confidence interval, 1.35-2.06) and CLI RP (odds ratio, 1.70; 95% confidence interval, 1.38-2.09) compared with patients with claudication. CONCLUSIONS The 30-day readmission rates after lower extremity bypass vary significantly by surgical indication. Because lower extremity bypasses are performed for multiple indications, if readmission rates are publically reported and hospitals can be penalized for higher than expected readmission rates, the expected readmission rates should be adjusted for surgical indication.