The National Board of Nutrition Support Certification (NBNSC) is an independent credentialing board responsible for administering certification programs in nutrition support. The NBNSC conducted a study (practice audit) of Nutrition Support Professionals (NSP), with the purposes of defining the role of the nutrition support professional and determining the current elements (knowledge or functions) required for competent NSP practice. This article describes the development of the study, results of the study, and use of the information for future certification in nutrition support. A list of the elements required for competent practice was gleaned from a variety of sources. A rating scale was developed to measure the importance of elements required for competent practice and frequency of practice. From this, an online survey instrument was prepared. Surveys were sent to 5964 NSPs; a total of 891 surveys were completed (return rate of 16.8%). There was 98% agreement among the disciplines of the perceived importance of the elements required of competent entry-level NSP practice; that the survey either completely or adequately described these elements; and that it reflected practice by region as well as among various disciplines and work settings. The results of the practice audit demonstrate a common core of practice (95%) across the nutrition support disciplines as well as a universal core of elements believed to be important for competent nutrition support practice. As a result, the NBNSC has developed 1 examination for future nutrition support certification testing and will confer 1 credential, Certified Nutrition Support Clinician (CNSC), to those who pass the exam.