BACKGROUND Although rare, iatrogenic left main coronary artery (LM) dissection is a feared complication of coronary catheterization. Its incidence, optimal therapeutic management, and prognosis remain largely unknown. The aim of the present study was to estimate the incidence, characterize the population at risk, depict the initial management, and evaluate the long-term prognosis of iatrogenic LM dissection. METHODS Thirty-eight patients who fulfilled the National Heart, Lung, and Blood Institute diagnostic criteria for iatrogenic LM dissection were retrieved from our database and followed up by telephone or physician visit. The primary end point was freedom from major adverse cardiac events (MACE) at 5 years. RESULTS The overall incidence of iatrogenic LM dissection during the study period was 0.07% (38/51,452 patients) and almost twice as common with percutaneous coronary intervention than coronary angiography. From 38 patients, 1 (3%) patient died before any therapeutic attempt was performed, 6 (16%) patients were treated conservatively, and 31 (82%) patients underwent stent implantation and/or coronary artery bypass grafting (CABG). In-hospital outcome was favorable irrespective of the therapeutic strategy. During the 5-year follow-up, among 31 patients who underwent revascularization treatment by stenting or CABG, one patient died in each group from a cardiac cause, and MACE were observed in 12 patients (39%). Kaplan-Meier cumulative survival estimates showed no significant difference between different revascularization treatment strategies. CONCLUSIONS Iatrogenic LM dissection is a rare complication of cardiac catheterization procedures with favorable early and long-term outcome when recognized timely and managed properly.