OBJECTIVE The Patient Protection and Affordable Care Act increases oversight of surgical outcomes and ties hospital readmissions to Medicare reimbursement. Given the increasing volume of outpatient urological procedures, to our knowledge this study provides the first multi-institutional multivariate analysis of patient factors that contribute to readmission. METHODS Using the 2011 National Surgical Quality Improvement Program database we identified 7,795 patients. Multiple logistic regression was used to predict 30-day unplanned hospital readmissions controlling for demographics, clinical characteristics and comorbidities. Readmission rates of the 5 most common procedures were calculated along with the rate of postoperative complications associated with readmission. RESULTS Outpatient urological surgery had an overall 3.7% readmission rate. The 5 most common procedures were cystourethroscopy and resection of bladder tumor (readmission rate 4.97%), laser prostatectomy (4.27%), transurethral resection of prostate (4.24%), hydrocele excision (1.92%) and sling surgery for urinary incontinence (0.85%). The most common comorbidities in readmitted patients were hypertension, diabetes and smoking. Risk adjusted multiple regression indicated that cancer history (OR 3.48), bleeding disorder (OR 2.03), male gender (OR 1.38), ASA(®) level 3 or 4 (OR 1.34) and age (OR 1.01) were significant predictors of readmission. Readmitted patients also had a higher 30-day complication rate. CONCLUSIONS Readmission after outpatient urological surgery occurs at a rate of 3.7%. A history of cancer, bleeding disorder, male gender, ASA level 3 or 4 and age were associated with readmission along with greater rates of medical and surgical complications. Our results may help guide risk reduction initiatives and prevent costly readmissions.