Study Objectives: Health equity for all patients is an important characteristic of an effective health care system. Implicit bias has the potential to create inequities. Utilization and throughput metrics are important quality metrics in emergency medicine where time to diagnosis and treatment can impact clinical outcomes. The objectives of our study were to investigate whether there are sex-based differences in chief concerns, method of arrival, arrival time of day, and length of stay (LOS) among ED patients.Methods: We conducted an observational cohort study of all adult patient visits to the ED of Mayo Clinic Hospital-Saint Mary's Campus, Rochester, Minnesota between July 2015 and June 2017. We included all adult patients 18 years and older seen in the ED who consented to the use of their medical records in research. We collected LOS, demographics including sex (patient's gender identity was not reported in the EHR at the time), chief concern, and mode of arrival, Differences in patient utilization between male and female patients were assessed using Chisquared tests. Follow-up pairwise comparisons were performed using chi-squared tests and p-values were adjusted using a false discovery rate correction. All tests were two-sided and adjusted p-values less than .05 were considered statistically significant. A clinically significant time difference was defined as 10 minutes a priori.Results: A total of 114, 826 adult visits from 67, 647 distinct patients were assessed. Male patients presented more often with general and unspecified complaints, psychological, cardiovascular, or urologic complaints.Female patients presented more often with digestive, neurologic, musculoskeletal, or genital complaints. The distribution of chief concerns were different between male and female patients with greatest distinction in digestive concerns (17.6% females, 12.9% males, p< .001). Male patients had a median arrival time to the ED of 15 minutes earlier in the day than female patients (p < .001). The length of stay for male and female patients was not significantly different.Conclusion: This study aimed to examine ED utilization and throughput between male and female patients. From this data, we did not identify any significant suggestion of sex-related bias in ED care. Future work is needed to assess whether length of stay is equitable during times when ED resources are most constrained.