A 68-year-old female patient was admitted at our hospital because of unstable angina pectoris. Coronary angiography revealed an 85% diameter stenosis in the proximal segment of the left anterior descending coronary artery (LAD) and a 70% diameter stenosis in the mid segment of the right coronary artery (RCA). Elective implantation of a Palmaz-Schatz stent in the LAD stenosis and conventional angioplasty of the RCA stenosis was decided for. Positioning of the Palmaz-Schatz stent was uneventful, whereas deployment of the stent, using a pressure of 10 atmospheres was complicated by balloon rupture, causing an extensive retrograde dissection of the LAD, involving the left main stem, the adjacent coronary sinus, and the proximal segment of the circumflex artery (CX). Coronary flow was stabilized by two guide wires inserted in the LAD and CX and the patient was sent to emergency operation. The postoperative course was uneventful and there were no signs of myocardial infarction.