Background:Tamsulosin is an α-1A-specific blocker which induces selective relaxation of ureteral smooth muscle with subsequent inhibition of ureteral spasms and dilatation of the ureteral lumen and facilitates stone expelling.Objectives:In this study we aimed to assess the efficacy of tamsulosin for improving the success rate of ureteroscopic lithotripsy (URS) for lower ureteral stones.Patients and Methods:In a prospective study by a randomized controlled clinical trial, which was performed from June 2008 to December 2010, we enrolled one hundred and forty-two subjects and eventually 102 patients completed the clinical trial. All the patients underwent ureteroscopic lithotripsy with the pneumatic wolf lithotripsy. The patients were randomly divided into 2 groups: the study group including 52 patients, received tamsulosin with our traditional treatment (hydration and analgesic when required), and the control group with 50 patients who received placebo with traditional treatment. The number of colic episodes, lower urinary tract symptoms, analgesic dosage, and days of spontaneous passage of the stones through the ureter were recorded in a diary after lithotripsy.Results:The results showed that tamsulosin treatment group had low expulsion time (P = 0.011), low urinary tract symptoms, least analgesic needs and low adverse effects, all with statistically significant differences comparable with the control group (P < 0.05).Conclusions:Administration of α-1A-specific blocker reduced analgesic dosage and colic episodes and rate of adverse effects after ureteroscopic lithotripsy of lower ureteral stones and decreased gravel expulsion time after URSL.