A 68-year-old woman with resistant essential arterial hypertension despite the regular use of four antihypertensive drugs was referred to the catheter-based renal sympathetic denervation. Due to the complicated anatomy, insertion of the guiding catheter into the left renal artery was not stable. Thus, renal denervation of only the right renal artery was performed. Before and after renal denervation, the patient's blood pressure was monitored by home blood pressure (BP) telemonitoring. The average 7-day home BP telemonitoring values before and 1, 2, and 3 months after denervation were 187.1/124.1, 193.3/123.1, 198.3/129.6, and 195.2/128.0 mm Hg. After unilateral renal denervation, no BP decrease occurred. This unique case suggests that unilateral catheter-based renal sympathetic denervation in resistant arterial hypertension shows no BP-lowering effect. Therefore, when treating resistant hypertension by catheter-based renal denervation, it seems advisable to try always to perform an effective bilateral procedure.