Stone fragments that develop after extracorporeal shock-wave lithotripsy (ESWL) may lodge within the ureter. This column of fragments is referred to as a "steinstrasse" (plural, steinstrassen). We evaluated the first 1000 patients treated with ESWL at our institution to determine the frequency of steinstrasse formation, the clinical course of patients with steinstrassen, and the types of intervention, if any, required. Steinstrassen were seen in 20% of 1000 patients treated with ESWL. In 65% of the patients studied, the steinstrassen passed spontaneously. Of the remaining patients, all but 3% required treatment for ureteral obstruction. Seventy-five percent were treated urologically (ureteroscopy, ureteral catheterization), but 25% required radiologically directed intervention, either percutaneous nephrostomy or fluoroscopically monitored retrograde ureteral catheter/stent placement. Twenty-seven percent of our patients with persistent steinstrassen had silent obstruction. In view of the insidious manner in which kidney function may be jeopardized by steinstrassen, they should be managed with great circumspection. Radiologists dealing with steinstrassen should be skillful in both antegrade and retrograde methods of urinary tract intervention.