A case of a 12 cm giant renal artery aneurysm (RAA) in an 59-year-old woman is reported. The patient was referred to our hospital for flank pain and spot hematuria. Ultrasonography (US) revealed some wide lacunar areas in her right kidney and a thin cortex. Three-dimensional computed tomography (3D-CT) revealed a giant right renal arteriovenous malformation (AVM). AngioCT scan showed a pervious right renal artery. The cavities of the right kidney were dilated and the parenchyma was markedly reduced. Two months later the patient underwent an open resection of the aneurysm and a right nephrectomy. She had an uneventful recovery and a healthy status (last follow-up: 9 month). In this particular case, a safe approach is the transabdominal approach since the aneurysm was very large, friable, and located on the right side. This report confirms the opportunity of a planned nephrectomy once there is adequate renal reserve in the opposite kidney using a midline approach.