Abstract Background Historically, inflammatory bowel disease (IBD) trials report high enrollment rates for white-caucasian patients. To promote initiatives towards diversifying patients enrolled in clinical trials, we assessed the reporting of race/ethnicity of patients enrolled in pharmaceutical clinical trials for ulcerative colitis (UC). Methods A previous systematic review of all placebo-controlled trials in adult patients with UC examining different therapeutic drug classes was performed from inception to December 2020. Trial and patient characteristics were summarized according to the type of variable. Categorical variables were summarized by displaying the number and percentage of trials or participants for each category. Continuous variables were summarized by displaying the weighted mean, weighted standard deviation, and range. Means and standard deviations (SD) were weighted by the number of participants in each trial. Results Descriptive statistics of trial and patient characteristics for, 95 induction trials and, 29 maintenance trials are summarized in Table, 1. Race was reported in, 37.9% (36/95) of induction studies, with most participants being White (86.3%;, 8610/9976). Furthermore, 21/36 (58.3%) studies reported race as White vs. non-White participants; and, 15/36 (41.7%) studies provided further breakdown, including Black (115/3414 patients [3.4%]), Asian (448/4136 patients [10.8%]), and “Other” (127/4136 patients [3.1%]). Moreover, 3/36 studies misreported race as ethnicity and, only, 3/36 studies reported ethnicities correctly, classifying patients as Hispanic/Latinx vs. Non-Hispanic/Latinx. For maintenance trials, 34.5% (10/29) studies reported race, with majority of participants being White (85.6%;, 2778/3246). Additionally, 6/10 studies reported only a White vs. non-White participants comparison, while, 4/10 reported other races, including Black (45/1145 patients [3.9%]), Asian (40/888 patients [4.5%]), and “Other” (26/1145 patients [2.3%]). No studies reported ethnicity. Conclusion Given the increasing burden of IBD in developing countries, differences amongst racial and ethnic groups are important to understand since they can influence disease phenotype, response to therapy, and safety outcomes.1 We found poor race reporting in UC clinical trials and observed that the vast majority of participants enrolled were White. These findings suggest that the population prevalence of UC amongst different racial groups is not reflected in clinical trial populations, being important to raise awareness of the existing barriers that prevent patients from accessing clinical trials. Reporting of race and ethnicity in UC clinical trials should be mandatory, and a requirement to enroll a certain percentage of non-White patients should be considered.2