Duplex collecting system of the kidney is a common congenital anomaly of the urinary tract. It is usually asymptomatic clinically with normal renal function. In rare instances, it may complicate with giant hydronephrosis. The following is a case of a middle aged woman with history of recurrent urinary tract infections (UTI) and flank pain diagnosed with bilateral partial duplex kidney complicated with unusual non-functioning lower moiety left giant hydronephrosis due to distal left ureteric stenosis which probably enhanced the reverse flow of urine together with YO-YO reflux. The left upper moiety was preserved and functioning. There was also right bifid ureter seen (Y Shaped). Advanced cross sectional imaging modalities has simplified the diagnosis of this condition. CaSe RepoRT Check for updatesOn radiological examination, ultra-sonogram of the abdomen revealed a large left side intra-abdominal cystic lesion occupying the left hemi-abdomen pushing the bowel and other solid organs to the right side.Computed Tomography Urography (CTU) with delayed images showed bilateral partialrenal duplex kidney. The right kidney appeared as partial duplex