Nowadays, the implantation of coronary endoprosthesis within the left main coronary artery is not considered as an absolute contraindication. Here, we show a case of acute occlusion within the left main coronary artery. This was resolved by implanting a stent during a programmed cardiac catheterization. It should be stressed that this problem was occurred without manipulating the left coronary tree. In addition, the patient was in cardiac arrest when the stent was implanted. Cardiopulmonary resuscitation was applied because of this condition.