There are several reports of multiple ectopic renal arteries (RA) in the literature. However, the ectopic origin of a single RA with a normal kidney position is rare. Knowledge of this variant is extremely important in clinical, surgical and radiological practice. Using MDCT angiography examination, we describe a rare case of a right kidney located in a normal lumbal position with a single ectopic thoracic renal artery originating in the thorax, above the diaphragmatic dome, at the level of the upper one-third of the T12 vertebral body. With an "S"-shaped course and a total length of 103 mm, this artery had an intratoracic portion of 38 mm. It crossed the diaphragm at 23 mm lateral to the right side of the TA, through a hiatus located on the lateral side of the right crus of the diaphragm. The right inferior phrenic artery arose from the left lateral wall of the right RA, 5 mm below the level of CT (45 mm distal to the right RA origin). Remarkably, this variant was associated with an area of proximal arterial stenosis, which produced signs and symptoms of hypertension secondary to renal arterial stenosis. To the authors' knowledge, this is the first reported case of a stenotic single ectopic thoracic renal artery associated with a normal kidney position.