BACKGROUND: Studies of adolescent and young adult (AYA) oncology end-of-life care utilization are critical because cancer is the leading cause of nonaccidental AYA death and end-of-life care contributes significantly to health care expenditures. This study was designed to determine the quantity of and disparities in inpatient utilization in the last year of life of AYAs with cancer. METHODS: The California Office of Statewide Health Planning and Development administrative discharge database, linked to death certificates, was used to perform a population-based analysis of cancer patients aged 15 to 39 years who died in 2000-2011. The number of hospital days and the inpatient costs were determined for each patient in the last year of his or her life, as were clinical and sociodemographic factors associated with high inpatient utilization. Admission patterns as death approached were also evaluated. RESULTS: The 12,883 patients were admitted for 40 days on average in the last year of life, and this cost $151,072 per patient in inpatient costs. As death approached, the admission rates and the percentage of all admissions occurring at nonspecialty centers increased. Five percent of patients used 20% of bed days in the last year (high utilizers). Factors associated with high utilization included younger age (15-30 years), Hispanic ethnicity, non-health maintenance organization insurance, and hematologic malignancies. CONCLUSIONS: AYA oncology decedents were admitted for 40 days in their last year of life. Subgroups with high utilization had distinct sociodemographic and clinical characteristics, and nonspecialty center admissions increased as death approached. This demonstrates the need for palliative care at nonspecialty centers. Future studies need to determine whether these patterns are goal-concurrent, include high utilizers, and monitor the effects of health care reform. Cancer 2018. (c) 2018 American Cancer Society.