Purpose/Objective(s) Precision medicine (PM) has revolutionized oncology; however, tumor biomarkers are derived primarily from a homogenous population, not reflective of the diverse cancer population. NRG Oncology (NRG) has completed large practice changing clinical trials and encouraged biospecimen collection. We evaluated differences between patients who participated in NRG prostate cancer (PCa) trials versus those who also participated in biospecimen collection. Our hypothesis was that disparities exist in the NRG biobank collection that could further compound inequities in PM. Materials/Methods NRG PCa trials closed before 2015 were analyzed for patients who consented to biospecimen collection. We used t-tests and chi-square tests for continuous and categorical variables, respectively. Spearman correlation coefficients were used to assess the association between zip code area deprivation index (ADI; assessed continuously and categorized by highest quartile vs lowest 3 quartiles) and median income for model testing. Logistic regression models were used to assess the effect of various demographic factors. Results Of 6721 randomized patients, 5485 (81.6%) consented to biospecimen collection. A smaller proportion of non-White patients consented to specimen collection as compared to those who did not consent (17.6% vs. 25.9%, respectively; p<0.0001). Furthermore, patients who resided in neighborhoods with a greater socioeconomic disadvantage, as indicated by a higher ADI, were also less likely to consent to specimen collection, when compared to those who had a lower ADI (45.7% vs. 41.5%, respectively; p = 0.0004), however, there was no difference in zip code median income between the two groups. In univariate logistic regression models, ADI (categorical and continuous) was associated with a decreased likelihood for specimen consent (OR = 0.85, OR = 0.99, respectively, p<0.05 for both). Hispanic/Latino (OR = 0.61, OR = 0.56) and non-White patients (OR = 0.59, OR = 0.57) were less likely to consent to biospecimen collection in models with ADI as a predictor (categorical and continuous, respectively, p<0.001 for all). Non-White patients were less likely to consent to specimen collection (OR = 0.54; p<0.0001) in the model with median income as a predictor, where median income was not significantly associated with likelihood of specimen consent. Conclusion Although >80% of NRG PCa trial participants consented to biospecimen collection, patients who were non-White, Hispanic/Latino or who lived in zip codes with higher ADI were less likely to participate in specimen collection. Recognition and further understanding of these disparities can lead to targeted, sustainable improvements for biospecimen collection on NRG PCa clinical trials so that biorepositories and PM approaches can better reflect the trial participants and overall population.