Simulations are commonly used in organizations as a means to train personnel in a cost-effective and safe manner. However, simulations differ in terms of the fidelity used to recreate the real world environment from PC-based to full motion flight simulators. Fidelity is one of the most widely used terms in the simulation literature; however, usage and meaning of the term vary greatly. Generally, fidelity can be conceptualized as the degree of similarity between the training situation and the operational situation that is being simulated. We know that simulator fidelity is a crucial element in maximizing the transfer of skills learned in the simulator to the operational context. One must ask, however, what type(s) of fidelity is needed and how much is needed for transfer of training to be effective? The difficulty in understanding fidelity arises from the multiple ways of classifying differences between the simulation and the simulated, and identifying how these differences affect aspects of training. At least nine distinct classifications of fidelity exist (i.e. functional, physical, psychological, experiential, action, equipment, environmental, objective and perceptual) all with different implications for the effective use of simulation in training programs. For example, an early mindset within the aviation simulation community took as an axiom that the highest levels of all types of fidelity would produce the best transfer of skill; however, empirical results challenged this stance. Rather, it has been found that the appropriate type and amount of simulator fidelity varies based on variables such as the nature of the task, the sophistication of the trainee, the training context, the stage of training, and the specific motor, perceptual, cognitive and other skills required by the task. The discussion and systematic research of the effects of simulator fidelity on transfer of training in the medical domain is beginning to emerge and can benefit from the accumulated knowledge of simulation usage in the aviation domain. To that end, the purpose of this poster is threefold: (1) to review the disparate conceptualizations of simulator fidelity, (2) to review the variables that interact with fidelity to impact training effectiveness in the aviation domain and postulate analogous relationships in the medical domain, and (3) to provide lessons learned from the aviation community in regards to the optimal use of simulator fidelity. The results of this analysis are relevant to the design and operation of medical training facilities as a robust understanding of the impact of simulator fidelity on training effectiveness is essential to optimizing training resources. Conflict of Interest: Authors indicated they have nothing to disclose.