Objective Hospital readmissions after surgical operations are considered serious complications and have an impact on health care-associated costs. The Centers for Medicare and Medicaid Services strongly encourage identification and ramification of factors associated with hospital readmissions after operations. Despite advances in endovascular surgery, lower extremity arterial bypass remains the "gold standard" treatment for severe, symptomatic peripheral arterial disease. The purpose of this study was to retrospectively review the factors associated with hospital readmission after lower extremity bypass surgery. Methods The 2013 lower extremity revascularization-targeted American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database and generalized 2013 general and vascular surgery NSQIP Participant Use Data File were used for this study. Patient, diagnosis, and procedure characteristics of patients undergoing lower extremity bypass surgery were assessed. Multivariate logistic regression analysis was used to determine independent risk factors for hospital readmission within 30 days after surgery. Results A total of 2646 patients (65% male, 35% female) were identified in the NSQIP database who underwent lower extremity open revascularization during the year 2013. Indications for operations included tissue loss (39%), rest pain (32%), and severe claudication (25%). Preoperative ankle-brachial indices were 0.4 to 0.9 (32%) and <0.4 (16.5%). A total of 425 patients (16%) were readmitted within 30 days of index operation. Risk factors associated with readmission included wound complication (odds ratio [OR], 8.54; 95% confidence interval [CI], 6.68-10.92; P <.001), need for reoperation (OR, 5.95; 95% CI, 4.45-7.97; P <.001), postoperative myocardial infarction (OR, 2.19; 95% CI, 1.25-3.83; P =.006), wound dehiscence (OR, 8.45; 95% CI, 4.54-15.71; P <.001), organ or space surgical site infection (OR, 7.62; 95% CI, 2.89-20.14; P <.001), postoperative pneumonia (OR, 2.66; 95% CI, 1.28-5.52; P =.009), progressive renal insufficiency (OR, 4.12; 95% CI, 1.52-11.11; P =.005), superficial surgical site infection (OR, 7.37; 95% CI, 5.31-10.23; P <.001), urinary tract infection (OR, 2.67; 95% CI, 1.42-5.01; P =.002), and deep wound infection (OR, 14.0; 95% CI, 7.62-24.80; P <.001). Conclusions Readmission after lower extremity bypass surgery is a serious complication. Various factors put a patient at high risk for readmission. Return to the operating room, wound infection, amputation, deep venous thrombosis, and major reintervention on bypass are independent risk factors for hospital readmission. Return to the operating room is associated with a 5.95-fold increase in hospital readmission.