The purpose of this study was to explore the impact of an obstetric emergency high-fi delity simulation on maternity nurses' perceived self-effi cacy levels at three different time points. Study Design: We used a quasi-experimental, repeated measures design. Methods: A convenience sample of maternity nurses recruited from three institutions within a single rural health care system participated in simulation exercises at an academic high-fi delity simulation center. They completed the Obstetric Nursing Self Effi cacy survey before, immediately after, and 2 months following the simulation. Results: Twenty-nine nurses were included in the analysis. All were women and Caucasian. Most (72.4%) had a baccalaureate nursing degree, with an average nursing experience of 11 years (range 1 to 44 years), and <5 years of OB experience (55.