With the widespread use of contemporary ultrasonographic techniques in the obstetric period, congenital hydronephrosis has become the most common initial presentation of ureteropelvic junction (UPJ) obstruction. Prior to this, infants often presented with an abdominal mass, and children presented with abdominal pain, nausea, and vomiting.Hematuria and urinary tract infections are also not uncommon presenting symptoms.

The application of radiographic studies, according to the pediatric urology paradigm, separates cases of congenital hydronephrosis due to UPJ obstruction from cases caused by other etiologies such as posterior urethral valves, megaureter, and vesicoureteral reflux.