Research on the distribution of health care expenditures among the U.S. population has shown that a small proportion of individuals, many of whom have chronic health conditions, accounts for a disproportionate share of total expenses. This analysis builds on previous work on the prediction and concentration of expenditures to examine which health conditions and health status measures, in addition to demographic characteristics, are most associated with high medical care costs. For this study we pool data from the 1996 through 2004 Medical Expenditure Panel Survey (MEPS) and predict annual expenditures for individuals with single and multiple chronic conditions. The analysis will focus on which measures of health status are most associated with being in the upper tail of the expenditure distribution.