Aberrant vessels is the most common cause of extriensic uretero–pelvic junction (UPJ) obstruction. Due to the left flank pain, 18-year-old male patient with UPJ obstruction due to aberrant vessels in left malrotated kidney and right renal cross ectopia without fusion, had been operated. Ureter was reconstructed and anastomosed anterior to the aberrant vessels after the Double-J-Stent has been placed. At the postoperative period there were improvements in the clinical symptoms and renal function.So, even in the later childhood surgical choice is still the acceptable treatment modality in such cases. To the best of our knowledge, although there are some papers about aberrant vessels which cause UPJ obstruction,there is no such a case with ipsilateral renal hydronephrosis due to aberrant vessels associated with contralateral renal cross ectopia without fusion.