In the current national debate regarding private insurance versus Medicaid expansion, understanding how insurance is associated with racial disparities in prostate cancer (CaP) outcomes has broad policy implications. In the current study, the authors examined the association between insurance status, race, and CaP outcomes. The Surveillance, Epidemiology, and End Results program identified 155,524 men aged < 65 years who were diagnosed with CaP from 2007 through 2014. The association between insurance and stage of disease at the time of presentation was examined. Among men with localized CaP, the associations between insurance and receipt of therapy and prostate cancer-specific mortality (PCSM) were determined. Compared with private insurance, men with Medicaid were more likely to present with metastatic disease (adjusted odds ratio [AOR], 4.27; 95% confidence interval [95% CI], 4.01-4.55), were less likely to receive definitive treatment (AOR, 0.67; 95% CI, 0.62-0.71), and had increased PCSM (adjusted hazard ratio, 1.83; 95% CI, 1.50-2.24), regardless of race. Significant interactions between race and insurance status indicated that insurance had more than an additive association with race. Among privately insured patients, disparities in PCSM (AOR, 1.2; 95% CI, 1.03-1.40 [P = .019]) and presentation with metastatic disease (AOR, 1.13; 95% CI, 1.06-1.21 [P<.001]) were observed. No disparities were observed among patients with Medicaid insurance with regard to PCSM (AOR, 0.79; 95% CI, 0.52-1.20 [P = .272]) and metastatic disease (AOR, 0.91; 95% CI, 0.80-1.03 [P = .139]). Racial disparities in the outcomes of patients with CaP were observed in privately insured cohorts, whereas these disparities appeared to be reduced among patients with Medicaid insurance. However, outcomes need to be improved overall. Whether the equality in outcomes for Medicaid is due to white and African American patients doing "equally poorly" or "equally well" is unclear. Cancer 2018;124:752-9. © 2017 American Cancer Society. © 2017 American Cancer Society.