The success of carotid artery stenting in preventing stroke requires a low risk of periprocedural stroke and death. A comprehensive training and credentialing process was prerequisite to the randomized Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) to assemble a competent team of interventionalists with low periprocedural event rates. Interventionalists submitted cases to a multidisciplinary Interventional Management Committee. This committee evaluated 427 applicants. Of these, 238 (56%) were selected to participate in the training program and the lead-in phase, 73 (17%) who had clinical registry experience and satisfactory results with the devices used in CREST were exempt from training and were approved for the randomized phase, and 116 (27%) did not qualify for training. At 30 days in the lead-in study, stroke, myocardial infarction, or death occurred in 6.1% of symptomatic subjects and 4.8% of asymptomatic subjects. Stroke or death occurred in 5.8% of symptomatic subjects and 3.8% of asymptomatic subjects. Outcomes were better for younger subjects and varied by operator training. Based on experience, training, and lead-in results, the Interventional Management Committee selected 224 interventionalists to participate in the randomized phase of CREST. We believe that the credentialing and training of interventionalists participating in CREST have been the most rigorous reported to date for any randomized trial evaluating endovascular treatments. The study identified competent operators, which ensured that the randomized trial results fairly contrasted outcomes between endarterectomy and stenting.