objective:the effecay and saftey of emergency extracorporeal shock wave lithotripsy(ESWL) in the manegment of obstructing ureteric stones versus expectant treatment was stidied. pateints and methods:the study included 232 patients with acute renal colic due to patients compeleted the period of followup.the mean age of theses patients was 42 years. stone sgreater than 5 mm and less than 10 mm in size and all were radio opaque. exclusion criteria included pregnacies fever and blood coagulation disorder. the patients were divided in to 2 groups: group 1 included 75patients treated by emergency ESWL group II:included 122 patients were treated by modulith SL 20 lithotrepserunder intravenous sedation