This study's purpose was to describe the practice patterns of nurse practitioners (NPs) in Tennessess—specifically, the demographic characteristics and health problems of their clients and the therapeutic services they provide. A random sample of NPs practicing 20 or more hours per week in primary care in Tennessee provided data on a total of 680 clients seen during one selected day of care. An instrument adapted from the National Ambulatory Medical Care Survey (NAMCS) allowed comparison of the NP findings with a national survey of office-based physicians in five areas: client demographics, client health status, diagnostic tests ordered, therapeutic interventions provided, and client disposition. Although many similarities were seen, differences included the tendency of NPs to care for more younger and female clients, to perform fewer office surgical procedures, and to provide more health teaching/counseling interventions.