Carotid endarterectomy (CEA) reduces the risk of stroke in symptomatic patients with high-grade carotid stenosis. In this study, we evaluated the long-term, societal cost-benefit ratio of endarterectomy using a decision analysis model. We reviewed the results of 150 CEAs performed at an academic center and established a Markov model comparing cohorts of patients who experienced transient ischemic attacks and then underwent observation, aspirin therapy, or CEA. The cost-effectiveness of CEA was estimated using perioperative complication rates from our review and from the North American Symptomatic Carotid Endarterectomy Trial. Stroke and mortality rates were estimated from the literature. Cost estimates were based on medicare reimbursement data. Among the 150 CEAs reviewed, complications included major stroke (0.67%), minor stroke (1.33%), myocardial infarction (1.33%), pulmonary edema (0.67%), and wound hematoma (3.33%). There were no deaths or intracerebral hemorrhages. Using complication rates from our review, CEA produced cost savings of $5730.62 over the cost of observation and $3264.66 over the cost of aspirin treatment. CEA extended the average quality-adjusted life expectancy 15.8 months over that of observation and 13.2 months over that of aspirin. Substituting the North American Symptomatic Carotid Endarterectomy Trial results, CEA yielded savings of $2997.50 over the cost of observation and $531.54 over the cost of aspirin. Quality-adjusted life expectancy was extended 13.8 months compared with observation and 11.2 months compared with aspirin therapy. This analysis demonstrates that when performed with low perioperative morbidity and mortality rates, CEA is a highly cost-effective therapy for symptomatic carotid stenosis and results in substantial societal cost and life savings.