Background: Accrual of underrepresented populations (URPs-racial and ethnic minorities, women, rural populations, and younger and older populations) to clinical trials has been historically low, hampering progress in cancer treatment, symptom intervention and prevention for all. In 2018, the Alliance for Clinical Trials in Oncology (Alliance), as a part of the NCI's National Clinical Trials Network (NCTN) and a Research Base for the NCI Community Oncology Research Program (NCORP) began a multi-pronged strategy to increase accrual of underrepresented minorities by race and ethnicity (URMs) to both treatment and cancer control trials conducted by the Alliance. Methods: Alliance leadership set a goal of 20% accrual for racial and ethnic minorities to all trials in 2018. The Health Disparities Committee (HDC) implemented several strategies over time including leadership promotion/expectation of goals; funding junior investigators and special projects focusing on URPs; working groups for specific populations in HDC; HDC co-chairs to selected protocols; translation services of patient facing materials; opening studies at NCORP Minority Underserved Sites; real time monitoring of accrual demographics, by Alliance and by site; protocols addressing aims for specific populations; closing protocol enrollment to majority populations; and increasing the study sample size to enroll additional minority participants to allow for analyzing intervention effects by subgroups. Results: Accrual data from 117 NCTN and NCORP trials led by Alliance was included from 2014-2022. Over time, accrual of racial and ethnic minorities increased from 13.6% to 25.3% for treatment and 13% to 21.5% for cancer control trials. This results in overall increase from 13.5 % to 23.6% of URMs for all trials, a 74.8% improvement. Conclusions: Intentional approaches to increase URMs has led to an increase in URM accruals to Alliance trials. Future strategies include implementation of the Alliance Patient Questionnaire to prospectively measure the prevalence of specific social determinants of health among patients enrolled to further expand the understanding and address the needs of unique population accrued to Alliance trials. In addition, accrual of women, rural populations, and younger and older adults (65+ years) are now being monitored over time to increase all URP accruals.