Background: Medicaid Expansion (ME) was introduced by the Affordable Care Act to improve access to care for low income individuals by increasing the annual income limits to 138% of the poverty line. However, not all states have elected to participate in ME. Using the National Cancer Database (NCDB), we sought to assess the effects of participation in ME on the four most common urologic malignancies. Methods: The NCDB was queried for bladder, prostate, kidney and testis cancer from 2012-2016, to span the time period two years before and two years after the main ME which took place in 2014. Trends in insurance status at time of diagnosis and effects on stage at presentation before and after ME were analyzed. Results: The percentage of patients with Medicaid coverage at the time of diagnosis for all four urologic malignancies increased significantly after 2014, with a commiserate decrease in the percentage of uninsured patients (Table). By 2016, significantly more patients had Medicaid coverage at diagnosis in ME states compared to those in Non-ME states (bladder 5.0% vs 2.5%, prostate 5.9% vs 2.2%, kidney 9.7% vs 4.1%, 19.5% vs 7.2%, all p < 0.01). However, the stage at presentation for all four urologic malignancies did not significantly differ for patients in ME versus non-ME states. Conclusions: Despite an increase in the proportion of patients with Medicaid coverage after 2014, surprisingly, there was not an associated change in stage at presentation for urologic malignancies in ME states. Further long-term analysis is necessary to evaluate if expanded Medicaid coverage impacts overall survival in this patient population.