To earn a registered dietitian (RD) or registered dietitian nutritionist (RDN) credential—two names for the same credential—you must meet the criteria established by the Commission on Dietetic Registration (CDR), the credentialing agency for the Academy of Nutrition and Dietetics, and pass an exam. The exam may be referred to as the CDR exam, the RD exam or the Registration Examination for Dietitians.

To earn the RD credential, you must pass the exam sponsored by the CDR, which is the national credentialing agency for the Academy of Nutrition and Dietetics. The goal of the exam is to test applicants’ knowledge of nutrition and dietetics—a quality assurance measure of sorts. Passing the CDR exam and earning the national RD credential will qualify you for licensure or certification in most states so you may begin working. Requirements for state-issued license or certification for dieticians vary by state. 

Understanding the goal of the CDR exam may help you better grasp its importance and help you prepare for the test.

Before you register for the exam, make sure you meet the eligibility requirements for the CDR exam.

To be eligible to take CDR’s Registration Examination for Dietitian Nutritionists, you must complete an ACEND-accredited supervised practice program (such as a dietetic internship) and meet CDR’s minimum degree requirement. Your dietetics program (not the degree itself) must be accredited by ACEND as part of the pathway that leads to CDR exam eligibility. Starting January 1, 2024, a graduate degree is the minimum requirement for individuals seeking eligibility for the Registration Examination for Dietitian Nutritionists. The graduate degree must be granted by a USDE-accredited institution (or foreign equivalent).

Those seeking knowledge in the fields of dietetics and public health may pursue Master of Public Health (MPH) coordinated degree programs, such as MPH/RD programs. To learn more about eligibility requirements and internship options, explore our guide to becoming a registered dietitian.

The CDR exam encompasses four content sections called domains. Each domain accounts for a different percentage of the exam content (i.e., the number of questions), as outlined in CDR’s current test specifications. Each section in the CDR exam comprises a different percentage of the final grade, as outlined in CDR’s Registered Dietitian Examination Test Specifications (Content Outline):

The CDR exam is a computer-based adaptive test, and research from the Journal of Computerized Adaptive Testing shows that computerized adaptive testing (CAT) is designed to improve measurement efficiency by reducing test length while maintaining acceptable measurement precision. Your answers will determine which questions you receive next. 

The CDR exam handbook for candidates [PDF, 1.5 MB] can be found on the Commission on Dietetic Registration’s website. It contains information about the exam format, scheduling and more. The exam is taken at a Pearson VUE test center. Your testing appointment totals 3.5 hours: 3 hours for the exam, 20 minutes for an introductory tutorial, and 10 minutes for a post-exam survey. There are 125 to 145 multiple-choice questions. Out of 125 questions, a student must answer 100 scored questions and 25 unscored pretest questions for the exam to be scored. Out of 145 questions, 120 scored questions and 25 unscored pretest questions must be answered. If a candidate answers fewer than 125 questions within the 3-hour testing period, the exam is scored as a failure because the result is inconclusive. The exam questions are designed to test either comprehension or application. 

An on-screen calculator is provided. 

When you are sure you meet the eligibility requirements and have been validated by CDR, you can take the CDR exam. You will be notified of your eligibility to schedule your exam via email by CDR’s testing vendor, Pearson VUE. The entire process, from the time CDR receives a candidate’s eligibility information to the time the candidate receives the Pearson VUE Authorization to Test email, typically takes less than a week (often within 48 hours once eligibility is approved).

Authorization expires after the test is taken or one year after receipt of the email, whichever occurs first. “If you do not pass the exam, you will need to reapply for authorization (online or by emailing CDR) before scheduling a retake. Candidates must wait 45 days between test attempts. There is no limit on the number of times you may take the exam, provided you wait the required 45 days between test dates.

The RD exam is administered year-round at more than 250 locations in the United States. You may search for a test center near you on the Pearson Vue website. The examination fee for dietitians is $250.

CDR’s published pass/fail statistics show that first-time pass rates typically fall in the mid-to-high 60% range (and can vary by eligibility pathway and reporting period). For example, in January–June 2025, the Coordinated Program pathway reported a 67.4% first-time pass rate, compared with 65.8% in January–June 2024. Looking beyond the first attempt, CDR also publishes a “pass within one year of first attempt” summary; for the period ending 2024, the pass-within-one-year rate was 85.38% for Coordinated Programs and 86.48% for Dietetic Internships. 

There is no one right way to prepare for the CDR exam. You know yourself best, and your study methods have gotten you this far already. That said, here are some tips you may find useful as you prepare for the exam:

The CDR exam may be challenging for some. Depending on the person, it can take several weeks or months of studying to fully prepare. Be sure to give yourself enough time, given your schedule and preparation style.

Set a realistic study schedule and decide what topics you will study at which times. You may write it down in a paper planner or use Google calendar to map out study blocks. Decide whether you will study alone or with other people and where. Some people concentrate better away from home.

There are a number of free materials available online to help you prepare for the CDR exam, as well as paid print, online, and audio materials. CDR provides official exam prep resources, including the RD test specifications (content outline), a study outline, references, and optional practice questions, and an online study guide. Other options include Inman Seminars’ print-and-audio review course for the RD exam and Mometrix Test Preparation study guides. To save costs, some students purchase used materials or share them with other students.

Note: CDR does not endorse any particular examination preparation program or offering. Purchasing a certification preparation product is not required and does not guarantee that an individual will pass the exam. 

Whether you use online testing tools, apps, flash cards or another method, practice may help you master the information.

On exam day, fuel up with a healthy breakfast, build in time for a solid night’s rest, and arrive early so you can settle in without added stress.

In addition to those mentioned, there are a variety of resources to help you prepare for the exam. When deciding on which ones to use, consider your budget, timeframe and how you learn best. You may need a combination of tools to really grasp the information. Here are a few to consider: 

RD Exam Handbook for Candidates. This free handbook from CDR explains key exam policies and logistics, including authorization to test, scheduling, payment, exam content, and score reporting.

Study Guide for the Registration Examination for Dietitians (11th Edition). This official study guide includes exam-prep tips and an online practice exam with questions similar in format to the real test.

Registration Examination for Dietitians Study Outline (2022–2026). This free CDR resource lists the current domains and topics covered on the RD exam and aligns with the test specifications/content outline. Students who have passed the exam recommend starting with the topics that are the most challenging to you.

EatRightPrep. The Academy of Nutrition and Dietetics offers this online RD exam prep tool. A 3-month subscription to eatrightPREP® for the RDN Exam includes three full-length practice tests plus two timed simulated tests, along with performance reports, rationales/references for each question, flashcards, and other study tools. A free 7-day demo is available.

RD Exam Study Suite software. This multiple-choice study guide created by an RD, resembles the actual RD exam. It includes practice exams with 1,300+ multiple-choice questions, whiteboard video tutorials, and other interactive study modules.

Pass the Exam Prep. This exam prep option teaches the Study Smarter Method, an evidence-based approach that focuses on using practice questions strategically (rather than relying on passive study habits). The RD who created the Study Smarter Method claims it is more efficient and effective than traditional study methods, such as reading and highlighting information. Formats vary, but it’s commonly offered as digital downloads (e-book, practice questions, and topic study guides), and some programs also offer physical + online binder-style versions.

Now that you know what’s involved in preparing for the CDR exam and earning the RD credential, you may feel better prepared to take this next step toward a career as a dietitian. The CDR exam may be challenging, but don’t let that stop you from pursuing your goal to become an RD.

Now that you know what’s involved in preparing for the CDR exam and earning the RD credential, you may feel better prepared to take this next step toward a career as a dietitian. The CDR exam may be challenging, but don’t let that stop you from pursuing your goal to become an RD.

Information last updated February 2026.