Objective: This study evaluated the competence of Advanced Cardiac Life Support certified personnel at hands-on ACLS skills. Methods: The observational, cross-sectional study assessed participants' subjective confidence and objective skills using the ACLS mega code examination. Testing was performed with a Laerdal manikin and standardized code carts. Results: Participants had a 12% (6% to 22%, 95% CI) pass rate for the stable tachyarrhythmia scenario and a 57% (44% to 69%, 95% CI) pass rate for the unstable tachyarrhythmia scenario. The most significant skills missed were appropriate medications and postconversion maintenance in the stable scenario and appropriate energy selection and successful shock delivery for the unstable scenario. Conclusions: ACLS providers feel confident in their ACLS skills; however, actual performance demonstrated poor performance in the management of patients with stable and unstable tachyarrhythmias. The recommendation is to observe initial and recertification ACLS classes to investigate the standard to which these core skills are being taught and evaluated.