Background: Most persons with dementia have multiple chronic conditions; however, it is unclear whether co-existing chronic conditions contribute to health-care use and cost. Methods: Persons with dementia and >= 2 chronic conditions using the National Health and Aging Trends Study and Medicare claims data, 2011 to 2014. Results: Chronic kidney disease and ischemic heart disease were significantly associated with increased adjusted risk ratios of annual hospitalizations, hospitalization costs, and direct medical costs. Depression, hypertension, and stroke or transient ischemic attack were associated with direct medical and societal costs, while atrial fibrillation was associated with increased hospital and direct medical costs. No chronic condition was associated with informal care costs. Conclusions: Among older adults with dementia, proactive and ambulatory care that includes informal caregivers along with primary and specialty providers, may offer promise to decrease use and costs for chronic kidney disease, ischemic heart disease, atrial fibrillation, depression, and hypertension.