Reliance on emergency departments (EDs) by economically disadvantaged people for initial cancer diagnosis in place of primary care and early diagnosis and treatment is 1 obvious plausible explanation for cancer disparities. Claims data from a safety net hospital for the years 2009-2010 were merged with hospital tumor registry data to compare hospitalizations for ED-associated initial cancer diagnoses to non-ED associated initial diagnoses. The proportion of initial cancer diagnoses associated with hospital admissions through the ED was relatively high (32%) for all safety net hospital patients, but disproportionately higher for African Americans and residents of the impoverished urban core. Use of the ED for initial diagnosis was associated with a 75% higher risk of stage 4 versus stage 1 cancer diagnosis, and a 176% higher risk of dying during the 2-year study period. Findings from this study of ED use within a safety net hospital documented profound disparities in cancer care and outcomes with major implications for monitoring disparities, Affordable Care Act impact, and safety net hospital utilization. (Population Health Management 2016;19:95-101).