Background: It is well established that ACE-inhibitors should be avoided in patients with renal artery stenosis. In recent years it has also been recommended that caution should be demonstrated when angiotensin II blockers are used in the same type of patients but the evidence is based only on few cases. Results: We describe a case where use of the angiotensin II antagonist candesartan (Atacand) induced renal failure in a patient with bilateral renal artery stenosis. The course of the case is enlighted by results from sequential renography, selective renal vein catheterisation for measurement of renin, and angiographic findings. Conclusions: In patients with renal artery stenosis the angiotensin II antagonist candesartan should be avoided.