INTRODUCTION: Emergency medicine (EM) is at a critical juncture with pervasive boarding and overcrowding, a rapid rise in new residency programs, and continuing recovery from the COVID-19 pandemic. These factors could all potentially impact trainees' learning experiences. To explore how this has influenced trainee knowledge acquisition, we analyzed the trends in the American Board of Emergency Medicine (ABEM) In-training Examination (ITE) and the written Qualifying Examination (QE). METHODS: This was a retrospective study of multiyear performance trends for the ITE (2018-2024) and QE (2019-2024). Only ITE results from residents in categorical ACGME-accredited EM programs were included. ITE performance was the aggregate mean scaled (equated) scores of all EM training levels. The measures for QE performance were the mean scaled scores (equated) and the pass rates. For each test, descriptive statistics were reported and an omnibus analysis of variance (ANOVA) comparing scores across years was computed. When an ANOVA result was statistically significant ( α  < 0.01), Tukey's tests were performed. RESULTS: For the ITE, there were 61,512 test results, of which 59,075 (96.0%) met inclusion criteria. The mean (SD) scaled ITE scores declined from 77.36 (8.85) in 2018 to 72.19 (9.44) in 2024. The ANOVA for the ITE scaled scores was statistically significant (p < 0.01). The QE had 17,040 test results, of which 15,651 (91.8%) met inclusion criteria. The mean (SD) scaled scores declined from 82.8 (4.6) in 2019 to 80.5 (4.5) in 2024, while the pass rate also declined from 92.3% in 2019 to 82.0% in 2024. The ANOVA for the QE scaled scores across years was significant (p < 0.01). CONCLUSIONS: Physician performance on the ABEM ITE has steadily declined since 2018; performance on the QE has declined since 2019. Future research is needed to understand and address the potential causes of these trends.