Objectives: In this study, an endovaginal ultrasound (US) task trainer was combined with a high-fidelity US mannequin to create a hybrid simulation model. In a scenario depicting a patient with ectopic pregnancy and hemorrhagic shock, this model was compared with a standard high-fidelity simulation during training sessions with emergency medicine (EM) residents. The authors hypothesized that use of the hybrid model would increase both the residents' self-reported educational experience and the faculty's self-reported ability to evaluate the residents' skills.Methods: A total of 45 EM residents at two institutions were randomized into two groups. Each group was assigned to one of two formats involving an ectopic pregnancy scenario. One format incorporated the new hybrid model, in which residents had to manipulate an endovaginal US probe in a task trainer; the other used the standard high-fidelity simulation mannequin together with static photo images. After finishing the scenario, residents self-rated their overall learning experience and how well the scenario evaluated their ability to interpret endovaginal US images. Faculty members reviewed video recordings of the other institution's residents and rated their own ability to evaluate residents' skills in interpreting endovaginal US images and diagnosing and managing the case scenario. Visual analog scales (VAS) were used for the self-ratings.Results: Compared to the residents assigned to the standard simulation scenario, residents assigned to the hybrid model reported an increase in their overall educational experience (D VAS = 10, 95% confidence interval [CI] = 4 to 18) and felt the hybrid model was a better measure of their ability to interpret endovaginal US images (D VAS = 17, 95% CI = 7 to 28). Faculty members found the hybrid model to be better than the standard simulation for evaluating residents' skills in interpreting endovaginal US images (D VAS = 13, 95% CI = 6 to 20) and diagnosing and managing the case (D VAS = 10, 95% CI = 2 to 18). Time to reach a diagnosis was similar in both groups (p = 0.053).Conclusions: Use of a hybrid simulation model combining a high-fidelity simulation with an endovaginal US task trainer improved residents' educational experience and improved faculty's ability to evaluate residents' endovaginal US and clinical skills. This novel hybrid tool should be considered for future education and evaluation of EM residents. The use of endovaginal US by emergency physicians (EPs) has demonstrated potential to decrease emergency department (ED) length of stay and to facilitate rapid assessment of patients with ruptured ectopic pregnancy.2,3 During the past 10 years, acquiring and interpreting US images has become an accepted part of the training of emergency medicine (EM) residents. The