INTRODUCTION: Immediate ureteroscopic treatment for patients presenting to the emergency room with symptomatic ureterolithiasis is more commonly being utilized. Recent reports demonstrate good efficacy for emergency ureteroscopy (URS); however, preoperative predictors of treatment success have not been described. In this study, we report our multicenter experience with emergency URS and identify predictors of successful treatment. We also describe the Emergency Ureteral Stone Treatment (EUST) score, which integrates these predictors and stratifies patients into those that are likely and unlikely to have successful treatment. MATERIALS AND METHODS: Laboratory and radiographic data for all patients who underwent emergency URS for acute symptomatic ureterolithiasis from 2010 to 2015 were reviewed. Statistical difference among parameters for patients who were stone free (SF) and not SF was assessed with the Student's t-test. Cutoff values for significant predictors were determined using sensitivity and specificity analysis. The EUST score was determined based on the number of cutoffs a patient was below. RESULTS: Two hundred two of 247 patients (81.8%) were SF. Two complications (ureteral perforation) occurred. Stone size, duration of symptoms before presentation, and serum white blood count at presentation did not affect SF rates. 95.5% of the treatment failures were attributed to a tight ureter preventing stone access. Patients who received alpha blockers before treatment were more likely to be SF (98.0% vs 55.5%, p < 0.01). Periureteral density (PUD) was lower in SF patients (2.8 HU vs 19.6 HU, p < 0.01), whereas the increase in serum creatinine from baseline (ΔCr) was greater in non-SF patients (0.44 mg/dL vs 0.20 mg/dL, p < 0.01). EUST score of 0, 1, and 2 correlated with SF rates of 20.6%, 81.9%, and 99.2%, respectively. CONCLUSIONS: Combined consideration of PUD and ΔCr with the EUST score can assist in selecting optimal candidates for immediate ureteroscopic management. Administration of alpha blockers before surgery may improve success rates by providing preoperative ureteral dilation.