Background: Complex renal artery aneurysms (RAA) involving major branches of renal artery are difficult to treat. Surgery may be associated with extensive invasiveness and morbidity in the context of major intra-abdominal surgery. Stentgrafts or selective coil embolization are contraindicated when large branches are involved in the aneurysmal sac. A case of the patient with complex renal artery aneurysm involving all major arterial branches treated with a new type of multilayer stent is described. Case report: A 56-year old woman whose right kidney had been removed five years before because of renal cell carcinoma was incidentally found to have a large (22 x 26 mm) saccular aneurysm in the main left renal artery involving all three major branches of the renal artery. Via a percutaneous femoral approach a multilayer stent was deployed without complications. Blood flow inside the sac was immediately and significantly reduced. All the renal branches remained patent. Conclusion: New multilayer fluid modulating stent concept appears to be a very useful and attractive alternative to surgery or other endovascular techniques for those RAA involving or very close to major branch vessels, especially in patients with very high risk of loosing the only viable kidney, as in our case.