e16553 Background: This population-based study assesses the relationship between insurance status and patterns of prostate cancer diagnosis and treatment among men under age 65. Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified 114,871 prostate cancer patients who were diagnosed before 65 between January 2007 and December 2013. Insurance type was classified as uninsured (3.1%), Medicaid (5.1%) and other including private insurance and coverage from the military or Veterans Affairs (91.8%). We used logistic regression model to quantify the relative risk of being diagnosed with metastasis or regional disease, and the relative likelihood of receiving radical prostatectomy or radiotherapy among those with localized cancer adjusted by, age, race, marital status, region, and diagnosis period. Results: Medicaid or uninsured patients are more likely to have late diagnosis (diagnosed with positive lymph node or metastasis) than patients with non-Medicaid insurance (Table 1). Among men diagnosed with localized prostate cancer, Medicaid and uninsured patients are less likely to receive prostatectomy. Medicaid patients are more likely to have radiotherapy than un-insured (see table). Conclusions: Compared with patients with non-Medicaid insurance, Medicaid and uninsured patients are more likely have late diagnosis and less likely to have radical prostatectomy for localized cancer, after accounting for differences in age, race, marital status, region, and diagnosis period. [Table: see text]