How to become a Registered Dietitian: the CDR exam explained

In the United States, becoming a Registered Dietitian (RD, also written RDN) means completing an accredited didactic program in dietetics, finishing a supervised practice component, and passing the Commission on Dietetic Registration (CDR) Registration Examination for Dietitians — a single national exam, so unlike some allied-health credentials, RDs sit the same exam body regardless of the state they practise in.

The three pieces, in order

• Didactic program — an ACEND-accredited bachelor's or graduate program covering nutrition science, food service systems, and clinical nutrition.
• Supervised practice — typically completed through a dietetic internship or an integrated graduate program combining coursework with supervised practice hours.
• The CDR exam — a computer-based, national exam covering food and nutrition science, nutrition care for individuals and groups, and managementfood service systems.

State licensure is a separate step

Passing the CDR exam and holding the RDRDN credential is necessary in most US states but is not always sufficient on its own — many states also require a separate state license to practise, administered by the state's own licensing board, on top of the national CDR credential. Confirm the requirement for your specific state directly with that state's board.

How to prepare

Because the CDR exam draws on both clinical judgment and food-service management content most candidates have not touched since early coursework, effective preparation mixes case-based nutrition-care scenarios with content review rather than pure recall. SimMedAi maps practice to the CDR exam specifically as one of its allied-health roles — see dietitian, or try a sample question at the demo.