Background: About 5% of men are newly-diagnosed with advanced stage prostate cancer (PCa) and experience far poorer survival compared to men diagnosed with local or regionally-advanced disease. PCa mortality is higher in African Americans (AA) compared to non-Hispanic whites (NHW), with a marginally higher proportion of AA men first diagnosed with advanced disease. Thus, we sought to describe recent trends in incidence, survival and patterns of treatment among men diagnosed with de novo AJCC stage IV PCa. Methods: SEER*Stat software was used to calculate age-adjusted rates and annual percent changes for PCa stratified by AJCC stage and race/ethnicity for men age 66 or older diagnosed 2004-2014. We then used the Surveillance, Epidemiology and End Results database linked to Medicare Claims files to identify men diagnosed with advanced PCa during same time period. We examined patterns of treatment among all eligible patients and by race/ethnicity. Results: Rates for AJCC stage I-III PCa among elderly men have significantly declined in recent years for both NHW and AA men (-5.8% APC, p<0.001 for both), while rates for AJCC stage IV increased for NHW men (+1.5% APC, p=0.011) and decreased for NHB men (-1.8% APC, p=0.008). Of the 8,828 eligible patients identified from the SEER-Medicare database, 13% were AA, with a median survival of 32 months among all patients and survival significantly poorer among AA (p < 0.0001). AA patients were also more likely to go without treatment (p < 0.0001) compared to NHW patients, even after accounting for early mortality and TNM stage. The frequency of nearly all forms of treatment was lower among AA patients with the exception of orchiectomy, which was significantly higher (10.1% vs. 6.1%), and among Medicare Part D enrollees, the progesterone Megace (24.6% vs. 15.0%). Conclusions: Results from this study of Medicare patients diagnosed with advanced stage PCa suggest less aggressive treatment may contribute to the poorer survival observed in AA men. Understanding drivers of treatment-related decisions are critical in reducing racial disparities in survival among men with advanced PCa.