Since the introduction and widespread use of extracorporeal shockwave lithotripsy (SWL), various complications have been noted. Perinephric hematoma and ureteral obstruction may be anticipated by urologists as potential problems. We report the first case of perinephric abscess encountered after 17 895 SWL treatments at our institution. A 65 year old woman presented 4 months following a second SWL procedure with a perinephric abscess and was successfully treated with percutaneous drainage. A review of the English literature revealed only 3 other cases of perinephric abscess following SWL. This diagnosis should be considered in early and late presentations of flank pain following SWL.