This paper describes a complication of selective femorocerebral catheterization which was due to iatrogenic embolization of atherosclerotic material originating from the bifurcation of the common carotid artery. After analysis of the catheter maneuvers inherent to the special shape of the type of catheter used (Sidewinder, Cordis Corporation), it is concluded that this complication resulted from incorrect catheter manipulation and an incorrect choice of the dimensions of the preshaped part of the catheter in relation to the diameter of the aortic arch. Two recommendations to avoid this complication are made.