141 Background: A key provision of the Affordable Care Act (ACA) was the expansion of Medicaid to childless adults living < 138% of the federal poverty level (FPL). Aside from a few early expansion states, the majority of states adopting the provision expanded coverage in January 2014, and are categorized as late expansion states (LES). Non-expansion states (NES) opposed expansion and did not adopt these broader provisions. Our objective was to determine the effects of this policy change on prostate cancer screening (PSAS) trends in LES and NES. Methods: The 2014 and 2016 Behavioral Risk Factor Surveillance System surveys reflect 2013 and 2015 health behaviors, and were queried for men 40-64, without history of prostate cancer, with a household income < 138% FPL, and residing in NES or LES. Descriptive statistics, stratified by expansion status and year, were generated for covariates. The Chi-Square test was used to compare proportions between years within state categories. Difference-in-differences (DID) analyses were employed to compare trends in men with health insurance, a personal physician, and undergoing PSAS. Within a multivariable logistic regression model, the interaction term year*state expansion status was used to determine the significance of DID estimates. Results: A weighted 8.8 million (n = 14,979) men met inclusion criteria. PSAS significantly declined from 2014 to 2016 in both NES (22.6% to 16.4%, p = 0.0006) and LES (20.5% to 15.8%, p = 0.003). In LES, the proportion of men with health insurance significantly increased from 2014 to 2016 (75.5% to 82.7%, p = 0.0002), however the proportion of insured men in NES was constant. Additionally, the proportion of respondents with a personal physician was unchanged from 2014 to 2016 in both NES and LES. DID analysis determined a significant difference in health insurance trends between 2014 and 2016 for LES compared to NES (+6.9%, p = 0.008). DID estimates were not significant for comparisons of trends for PSAS or access to a personal physician. Conclusions: The ACA’s Medicaid expansion provision has led to significant gains in insurance coverage for eligible persons in LES compared to NES, however, these gains have not translated into significantly different rates of access to a personal physician or PSAS.