Duplication of the ureter and renal pelvis is the most common upper urinary tract anomaly with a reported incidence of 0.8%1 in the population and in 1.8%–4.2% of pyelograms.2 5 The vast majority of these anomalies have normally developed renal moieties and cause nonfunctional problems. However, they can challenge the diagnostic acumen with a wide variety of manifestations. Complete duplex systems may be associated with vesicoureteral reflux (VUR) or may be ectopic or subtended by an ectopic ureterocele. Incomplete duplex systems are most often associated with ureteroureteral reflux or ureteropelvic junction obstruction of the lower pole of the kidney.6 , 7