The primary objective of this study is to compare the safety and performance of the Palmaz Genesis™ balloon expandable stent, with or without sirolimus coating in the treatment of renal artery stenosis, measured at 6 months follow up via angiography.

Multi-center, prospective, controlled, non-randomized investigational feasibility study. One hundred (100) patients with de novo or restenotic renal artery lesions consisting of >= 50% stenosis and reference vessel of >= 4.0 to <= 8.0 mm in diameter will be sequentially included, 50 without sirolimus coating, followed by 50 with sirolimus coating Palmaz GenesisTM. Patients will be followed for 24 months post-procedure, with all patients having clinical assessments at discharge, 1,6, 12 and 24 months. This study will be conducted at twelve investigational sites.

It is anticipated that the total length of time required to complete the study will be 46 months.

Inclusion Criteria:

1. Clinical indication for renal artery revascularization of atherosclerotic renal artery stenosis >=50% as measured by operator or estimated original vessel diameter, based on healthy vessel segment and contralateral side.
2. The reference vessel renal artery must be >= 4mm and <= 8 mm by visual estimate.
3. The patient must have a baseline serum creatinine of <= 5.0 mg/dl.

Exclusion Criteria:

1. Total occlusion of the renal artery.
2. Lesions which would require more than 2 stents.
3. Lesions which are in arteries to transplanted or bypassed kidneys.
4. Abdominal aortic aneurysm > 4.0 cm in diameter.
5. Patients with ASA classification >=4.