Background: Plasma C-Reactive Protein (CRP) is an acute-phase protein whose serum level increases in response to inflammation, as happens in impacted ureteric calculus. Few studies have investigated the efficacy of silodosin, a selective alpha 1-A adrenoceptor antagonist, in medical expulsive therapy (MET) for distal ureteral calculi. The studies showed the efficacy of silodosin 8 mg/day as a potential treatment for distal ureteric calculus expulsion. In this study wedetermined the correlation of CRP Levels at the starting of MET and the success of METwith SILODOSIN after 3 weeks.