Background: Critical thinking and self-confidence are imperative to success in clinical practice. Educators should use teaching strategies that will help students enhance their critical thinking and self-confidence in complex content such as electrocardiogram interpretation. Therefore, teaching electrocardiogram interpretation to students is important for nurse educators. Purpose: This study compares the effect of simulation-based and traditional teaching methods on the critical thinking and self-confidence of students during electrocardiogram interpretation sessions. Methods: Thirty undergraduate nursing students volunteered to participate in this study. The participants were divided into intervention and control groups, which were taught respectively using the simulation-based and traditional teaching programs. All of the participants were asked to complete the study instrument pretest and posttest to measure their critical thinking and self-confidence. Results: Improvement was observed in the control and experimental groups with respect to critical thinking and selfconfidence, as evidenced by the results of the paired samples t test and the Wilcoxon signed-rank test (p G .05). However, the independent t test and MannYWhitney U test indicate that the difference between the two groups was not significant (p 9 .05). Conclusions/Implications for Practice: This study evaluated an innovative simulation-based teaching method for nurses. No significant differences in outcomes were identified between the simulator-based and traditional teachingmethods, indicating that well-implemented educational programs that use either teaching method effectively promote critical thinking and self-confidence in nursing students. Nurse educators are encouraged to design educational plans with clear objectives to improve the critical thinking and self-confidence of their students. Future research should compare the effects of several teaching sessions using each method in a larger sample.