Hydronephrosis and urinoma are extremely rare complication of the abdominal aneurysm. A case of the aorto-iliac aneurysm associated with right hydronephrosis and urinoma is reported. The patient is 71 year-old female. She was admitted because of right lower abdominal pain. A diagnosis of the infrarenal abdominal aneurysm with involvement of the common iliac artery and right hydronephrosis due to ureter obstruction was made. A leakage of urine from right renal pelvis (urinoma) was also confirmed. A staged treatment for hydronephrosis was selected. At first, percutaneous nephrostomy was made under ultrasonographic guidance. Urinoma was completely disappeared thereafter. Two weeks later, the aneurysm was replaced with a Y-shaped Dacron graft and the right ureter was mobilized from the perianeurysmal fibrous tissue. On the 35th postoperative day, balloon ureteroplasty was performed through the nephrostomy catheter. Three months after operation, nephrostomy catheter was successfully withdrawn because of improved urinary passage through the right ureter. We emphasize the efficacy of staged surgical treatment combined with percutaneous nephrostomy for the abdominal aneurysm associated with hydronephrosis.