Issue: Finding ways to improve outcomes and reduce spending for patients with complex and costly care needs requires an understanding of their unique needs and characteristics. Goal: Examine demographics and health care spending and use of services among adults with high needs, defined as people who have three or more chronic diseases and a functional limitation in their ability to care for themselves or perform routine daily tasks. Methods: Analysis of data from the 2009–2011 Medical Expenditure Panel Survey. Key findings: High-need adults differed notably from adults with multiple chronic diseases but no functional limitations. They had average annual health care expenditures that were nearly three times higher—and which were more likely to remain high over two years of observation—and out-of-pocket expenses that were more than a third higher, despite their lower incomes. Rates of hospital use for high-need adults were more than twice those for adults with multiple chronic conditions only; high-need adults also visited the doctor more frequently and used more home health care. Costs and use of services also varied widely within the high-need group. Conclusion: These findings suggest that interventions should be targeted and tailored to high-need individuals most likely to benefit.