Sympathetic activation contributes to the progression of CKD and is associated with adverse cardiovascular outcomes. Ablation of renal sympathetic nerves reduces sympathetic nerve activity and BP in patients with resistant hypertension and preserved renal function, but whether this approach is safe and effective in patients with an estimated GFR (eGFR) , 45 ml/min per 1.73 m2 is unknown. We performed bilateral renal denervation in 15 patients with resistant hypertension and stage 3?4 CKD (mean eGFR, 31 ml/min per 1.73 m2). We used CO2 angiography in six patients to minimize exposure to contrast agents. Estimated GFR remained unchanged after the procedure, irrespective of the use of CO2 angiography. Mean baseline BP 6 SD was 174622/91616 mmHg despite the use of 5.661.3 antihypertensive drugs. Mean changes in office systolic and diastolic BP at 1, 3, 6, and 12monthswere234/214,225/211,232/215, and233/219 mmHg, respectively. Night-time ambulatory BP significantly decreased (P,0.05), restoring a more physiologic dipping pattern. In conclusion, this study suggests a favorable short-term safety profile and beneficial BP effects of catheter-based renal nerve ablation in patients with stage 3?4CKDand resistant hypertension.