Internal medicine residents in the US must be competent to perform procedures including Advanced Cardiac Life Support (ACLS) to become board-eligible. Our aim was to determine if residents near graduation could assess their skills in ACLS procedures accurately. Participants were 40 residents in a university-based training program. Self-assessments of confidence in managing six ACLS scenarios were measured on a 0 (very low) to 100 (very high) scale. These were compared to reliable observational ratings of residents' performance on a high-fidelity simulator using published treatment protocols. Residents expressed strong self-confidence about managing the scenarios. Residents' simulator performance varied widely (range from 45% to 94%). Self-confidence assessments correlated poorly with performance (median r = 0.075). Self-assessment of performance by graduating internal medicine residents was not accurate in this study. The use of self-assessment to document resident competence in procedures such as ACLS is not a proxy for objective evaluation.