Multiple chronic conditions (MCCs) are associated with increased intensity of end-of-life (EOL) care, but their effect is not well explored in patients with cancer. We examined EOL health care intensity and advance care planning (ACP) documentation to better understand the association between MCCs and these outcomes. Retrospective cohort study. Patients aged 18+ years at UW Medicine who died during 2010-2017 with poor prognosis cancer, with or without chronic liver disease, chronic pulmonary disease, coronary artery disease, dementia, diabetes with end-stage organ damage, end-stage renal disease, heart failure, or peripheral vascular disease. ACP documentation 30+ days before death, in-hospital death, and inpatient or intensive care unit (ICU) admission in the last 30 days. We performed logistic regression for outcomes. Of 15,092 patients with cancer, 10,596 (70%) had 1+ MCCs (range 1-8). Patients with cancer and heart failure had highest odds of hospitalization (odds ratio [OR] 1.67, 95% confidence interval [CI] 1.46-1.91), ICU admission (OR 2.06, 95% CI 1.76-2.41), or in-hospital death (OR 1.62, 95% CI 1.43-1.84) versus patients with cancer and other conditions. Patients with ACP 30+ days before death had lower odds of in-hospital death (OR 0.65, 95% CI 0.60-0.71), hospitalization (OR 0.67, 95% CI 0.61-0.74), or ICU admission (OR 0.71, 95% CI 0.64-0.80). Patients with ACP 30+ days before death had lower odds of high-intensity EOL care. Further research needs to explore how to best use ACP to ensure patients receive care aligned with patient and family goals for care.