New discoveries in the field of genetics and recent developments in newborn screening have created opportunities and challenges for genetic metabolic dietitians, placing increasing demands on dietitians to plan appropriate nutritional interventions for patients with metabolic disorders. An appropriate assessment tool must be developed to identify gaps in training and knowledge to assure that dietitians are prepared for advances in this emerging field. Using a multistage process, the Genetic Metabolic Dietitians International founders group developed a set of professional standards modeled after the American Dietetics Association's Standards of Professional Practice and the National Coalition for Health Professions Education in Genetics's core competencies. The Standards of Professional Practice for Genetic Metabolic Dietitians were validated by means of an electronic questionnaire distributed nationally to dietitians through the PRO-METLAB listserv. Statistical measures were used to determine whether perceived importance was significantly associated with compliance for each of the indicators included in the Standards of Professional Practice. The Standards of Professional Practice for Genetic Metabolic Dietitians will be used to structure continuing education opportunities, guide research and evaluation, and will serve as a basis for certification and professional accreditation.