Clinical practice has benefited from new methodologies such as realistic simulation (RS). RS involves recreating lifelike scenarios to more accurately reflect real clinical practice, enhancing learners' skills and decision-making within controlled environments, and experiencing remarkable growth in medical education. However, RS requires substantial financial investments and infrastructure. Hence, it is essential to determine the effectiveness of RS in the development of skills among medical students, which will improve the allocation of resources while optimizing learning. This cross-sectional study was carried out in the simulation laboratory of a medical school, and the performance of students who underwent two different curriculum matrices (without RS and with RS, from 2021 to 2022) in the Advanced Cardiac Life Support (ACLS) course was compared. This test was chosen considering that the competencies involved in cardiac life support are essential, regardless of the medical specialty, and that ACLS is a set of life-saving protocols used worldwide. We observed that the impact of RS can be different for practical abilities when compared with the theoretical ones. There was no correlation between the general academic performance and students' grades reflecting the RS impact. We conclude that RS leads to less remediation and increased competence in practical skills. RS is an important learning strategy that allows repeating, reviewing, and discussing clinical practices without exposing the patient to risks.