Introduction: Simulation training is a key part of healthcare and medical education, but the use of standardized patients in simulation training is not yet systematic at least in Finland. The purpose of this literature review was to determine the benefits and challenges of using standardized patients in simulation training. Methods: The information search was conducted in the international Cinahl and Pubmed databases. The search terms used were "Simulation", "Simulation-based education", "Simulated patient", "Standardized patient" and "Standardized patient". The inclusion criteria were 1) peer-reviewed original research 2) published in Finnish or English 3) published in the last 10 years. Additionally, the research had to be conducted in Europe, the United States, Canada, or Australia. 40 studies fulfill the criteria. The data was analyzed with inductive content analysis. Results: The use of a standardized patient in simulation training improves student learning outcomes, as well as develops interaction and work-life skills. For the standardized patient, participating in simulation training can increase acting experience and bring content to everyday life. However, it can also be physically and mentally taxing. It's important that the teacher enables good preparation for the role. Challenges experienced by students are related to stress created by the standardized patient and unexpected situations in the simulation of standardized patients. Discussion: The results show that the utilization of standardized patients in simulation requires planning and adequate resources, but it also brings various benefits, especially for the development of students' skills.