Spontaneous coronary artery dissection is a rare and generally fatal disease. A review of the literature demonstrates that the aetiopathogenesis of the disease is unknown and that the histology is rarely described. It usually occurs in young women during the post-partum period or while taking oral contraceptives. The treatment depends on the clinical presentation and the results of the angiography. We report here a case of spontaneous dissection of the left main stem coronary artery, with extension into the left coronary territory which which occurred in a 43-year-old woman.