Twenty-two unilateral nonobstructing radiopaque ureteral calculi were found on excretory urography in 21 patients over a 6-year period. The calculi were frequently (12/22) not associated with pain at the time of urography. Of the 21 patients, 19 had intrarenal pelvis configuration which may limit the potential dilatation of the collecting system. Twelve calculi eventually passed spontaneously and two were removed surgically. Three remained in the ureter for prolonged periods (up to 18 months), still nonobstructing. The majority (13/22) of the calculi were in the distal third of the ureter.