The functional and health characteristics of nursing home residents in New York State using a multivariate classification procedure are examined in this article. This analysis suggested that these characteristics could be explained in terms of six dimensions. The association of these six dimensions with two existing sets of nursing home case-mix groups was analyzed in order to determine how groups based only on the health and functional characteristics of residents related to groups based primarily on measures of current service use. A number of resident characteristics were not described well by case-mix measures based only on service use, suggesting the need to modify such groups using additional sources of input.