Abstract： Objective To study the impact of preprocedure intravenous urography(IVU)on the outcome of shock wave Iithotripsy(SWL)for the middle and lower ureteral stones.Methods 112 patients with solitary radiopaque the middle and lower ureterat stones on plain radiographs and no severe hydronephrosis on ultrasonographic examination were divided randomly to two treatment groups.IVU group(n=56)had IVU before the start of SwL,whereas patients in the control group(n=56)underwent SWL without IVU.Postoperative success,stone-free rates and complications were evaluated in both groups.Results Eleven patients in the IVU group were excluded from the study.The SUCCESS rate[91.1%(41/45)in IVP group VS 94.6%(53/56)in control group],stone-free rate[88.9%(40/45)vs 89.3%(50/56)],and complication rate[22.2%(10/45)vs 21.4%(12/56)]were similar in two groups(P＞0.05).ConclusionIt is not necessary to obtain an IVU for patients who have solitary radiopaque the middle and lower calculi on plain radiographs with no severe hydronephrosis on ultrasonographic examination before scheduling them for SWL,thus minimizing the cost,avoiding exposure to contrast medium,and reducing radiation exposure.