© 2015 American Cancer Society. BACKGROUND Rigorous processes ensure quality of research and clinical care at National Cancer Institute-designated comprehensive cancer centers (NCICCCs). Unmeasurable elements of structure and process of cancer care delivery warrant evaluation. To the authors' knowledge, the impact of NCICCC care on survival and access to NCICCCs for vulnerable subpopulations remain unstudied. METHODS The current study's population-based cohort of 69,579 patients had newly diagnosed adult-onset (aged 22-65 years) cancers reported to the Los Angeles County cancer registry between 1998 and 2008. Geographic information systems were used for geospatial analysis. RESULTS With regard to overall survival across multiple diagnoses, patients not receiving their first planned treatment at NCICCCs experienced poorer outcomes compared with those treated at NCICCCs; differences persisted on multivariable analyses after adjusting for clinical and sociodemographic factors (hepatobiliary: hazard ratio [HR], 1.5; 95% confidence interval [95% CI], 1.4-1.7 [P<.001]; lung: HR, 1.4; 95% CI, 1.3-1.6 [P<.001]; pancreatic: HR, 1.5; 95% CI, 1.3-1.7 [P<.001]; gastric: HR, 1.3; 95% CI, 1.1-1.7 [P =.01]; breast: HR, 1.3; 95% CI, 1.1-1.5 [P<.001]; and colorectal: HR, 1.2; 95% CI, 1.0-1.4 [P =.05]). With regard to barriers to care, multivariable analyses revealed that a lower likelihood of treatment at NCICCCs was associated with race/ethnicity (African-American: OR range across diagnoses: 0.4-0.7 [P<.03]; Hispanic: OR range, 0.5-0.7 [P<.04]); lack of private insurance (public: OR range, 0.6-0.8 [P<.004]; uninsured: OR range, 0.1-0.5 [P<.04]); less than high socioeconomic status (high-middle: OR range, 0.4-0.7 [P<.02]; middle: OR range, 0.3-0.5 [P<.001]; and low: OR range, 0.2-0.6 [P<.01]), and residing >9 miles from the nearest NCICCC (OR range, 0.5-0.7 [P<.02]). CONCLUSIONS Among individuals aged 22 to 65 years residing in Los Angeles County with newly diagnosed adult-onset cancer, those who were treated at NCICCCs experienced superior survival compared with those treated at non-NCICCC facilities. Barriers to care at NCICCCs included race/ethnicity, insurance, socioeconomic status, and distance to an NCICCC. Cancer 2015;121:3885-3893.