Background: Patient safety is an essential responsibility of nurses. However, newly graduated nurses experience patient safety incidents due to a lack of patient safety competency. In particular, intensive care unit nurses provide care to critical patients, making it difficult for new nurses to maintain patient safety. Therefore, it is necessary to improve the patient safety competency of newly graduated nurses working in the intensive care unit. Objectives: To analyze the effects of a simulation-based training program on patient safety management on the patient safety competency, patient safety management activity, communication self-efficacy, and teamwork of newly graduated nurses working in an intensive care unit. Design: A quasi-experimental study. Settings: The study was conducted at a university in Korea. Participants: A total of 44 newly graduated nurses working in the intensive care unit of a university hospital. Methods: A simulation-based training program on patient safety management was applied to the experimental group (n = 22), while only the usual hospital training program was used for the control group (n = 22). A structured questionnaire survey comprising Patient Safety Competency Self-Evaluation, Patient Safety Management Activities, the Korean version of the self-efficacy questionnaire, and K-self assessment of teamwork was conducted at baseline test (T1), post test (T2), and follow-up test (T3). Data were analyzed using a repeated measures ANOVA. Results: The experimental group showed significantly higher patient safety competency, patient safety knowledge, and patient safety skills, along with higher communication self-efficacy scores than the control group (p < .05) after the intervention and at four weeks after the intervention. Conclusions: The simulation-based training program on patient safety management effectively improved the patient safety competency, patient safety knowledge, and patient safety skills as well as communication self-efficacy of newly graduated nurses working in an intensive care unit.