Background Tamsulosin,an alpha-1 receptor antagonist,has been demonstrated effective in promoting distal ureteralstone passage and in reducing pain associated with stone expulsion.This study aimed to evaluate the effect oftamsulosin in comparison with nifedipine and extracorporeal shock wave lithotripsy(ESWL)on the expulsion rate of distalureteral stones at different sizes.Methods We assigned 314 patients to three categories:Ⅰ,the stone with maximal diameter of 4.0-5.9 mm;Ⅱ,6.0-7.9mm,and Ⅲ,8.0-9.9 mm.Patients in each category were randomly subdivided into three treatment subgroups:group A(nifedipine group),group B(tamsulosin group),and group C(ESWL group).Stone-free rate and the dose of analgesicswere recorded weekly during the 4-week follow-up period.Results Three hundred and three patients completed the study.The results showed that nifedipine and tamsulosintreatments promoted a small(4-8 mm,categoriesⅠandⅡ)stone expulsive rate that was comparable with ESWLtreatment.Nonetheless,when the stone diameter was 8.0-9.9 mm,ESWL showed a greater stone free rate thannifedipine and tamsulosin treatments;no significant difference existed between the latter two therapies.Although theESWL treatment group required the least analgesics,tamsulosin treatments required less pain medication than nifedipine(P<0.05).Conclusions Tamsulosin treatment is recommended for patients with the stone diameter smaller than 8mm becauseof its feasibility,effectiveness and safety.ESWL is more appropriate than tamsulosin therapy for the patients whosestones are larger than 8mm.