In this report, we describe the management of a 45-year-old type 2 diabetic who underwent a paediatric en bloc renal transplant, subsequently developing unilateral hydronephrosis. Of the 10 paediatric en bloc transplants performed by our unit over the last 30 years, this complication has only presented once. The 9-month-old graft kidneys were transplanted via the Lich-Gregoir technique, using two separate ureteric implants. Both stents were removed two weeks post transplant. The patient’s serum creatinine was 109 μmol/L at the time but started to rise by post operative week 4, with ultrasound demonstrating unilateral hydronephrosis of the laterally placed kidney. Once a nephrostogram confirmed this diagnosis, an antegrade ureteric stent was placed and kept in situ for one month. Following removal of the stent, serum creatinine started to rise again, with ultrasound and nephrostogram confirming the recurrence of the unilateral hydronephrosis. Re-stenting was performed, and the patient’s creatinine gradually decreased. Whilst common practise in such cases would be to explant the affected kidney, our team elected to re-explore the transplant site and surgically correct the obstruction. This was achieved by going through the previous incision using hydrodissection and identifying the ureter with ultrasound assistance. The distal ureter was found to contain a long strictured portion that was excised and reconstructed using a Boari flap. The patient’s creatinine subsequently reduced to 90μmol/L by three months post transplant, and on four year follow up was 51μmol/L. This is the first time this procedure has been described in literature, offering an alternative approach to the management of unilateral hydronephrosis.