Background: Utilizing race and ethnicity data from the Accreditation Council for Graduate Medical Education (ACGME), this study aims to assess representation trends across American Society of Clinical Oncology (ASCO) participant specialties from the past five academic years in order to characterize current needs and effectively address these needs moving forward. Methods: Self-reported ethnicity/race data from the ACGME database books were collected from academic years 2015-16 to 2019-2020 for the following oncologic training programs: hematology and medical oncology, medical oncology, gynecologic oncology, pediatric hematology and oncology, radiation oncology, complex general surgical oncology. Summary statistics and chi-square analysis were conducted to compare underrepresented minority (URM) trends across programs. URM groups were cross-referenced with definitions provided by the AAMC and included those who identify as Hispanic, Latino or of Spanish origin, Black or African American, and Native American or Alaskan. Results: Over the study period, only 1,250 (9.0%) of 13,853 oncology trainees identified as URM. Chi-square analysis demonstrated no significant change in URM representation in all oncology specialties combined between 2015-16 and 2019-20 (8.9% [95% CI, 7.8%-10.0%] vs. 9.7% [95% CI, 8.7%-10.8%]; P=.31). Between 2015-16 and 2019-20, Hematology and oncology (+1.3%), pediatric hematology and oncology (+0.3%) all demonstrated insignificant increasing trends in representation while radiation oncology (-0.3%), complex general surgical oncology (-4.0%) had statistically insignificant decreasing trends in representation. Gynecologic oncology (+6.0%) demonstrated a significant increasing trend in representation. Conclusions: This is the first study to characterize the vast disparities in representation in oncologic training programs in the United States. There is a demonstrated lack of representation across all oncology training programs and a lack of significant improvement over the study period. A multiprong approach is needed to improve diversity and representation across the spectrum of the oncology workforce in the United States.