After more than 20 years a new NRC for dairy cattle has been published. The National Research Council (NRC) is now referred to as the National Academies of Science, Engineering and Medicine (NASEM) so we need to get used to saying NASEM for dairy. All aspects of dairy nutrition were reviewed and recommendations or requirements were evaluated and updated when necessary for energy, protein and amino acids, carbohydrates, fats, minerals and vitamins. Requirements were produced for young calves, growing heifers, dry cows, and lactating cows. When possible large datasets were collated and used to derive new equations for both nutrient supply and requirements. New equation to estimate dry matter intake for growing animals, dry cows and lactating cows were developed. The energy system used in NRC 2001 was fine-tuned and improved. The protein system used in NRC was mostly replaced and is now based very heavily on amino acids. Recommendations for various carbohydrate fractions (e.g., fiber, starch and sugars) were made based on available scientific literature. Changes from NRC 2001 would be considered evolutionary, not revolutionary. All mineral and vitamin requirements were reevaluated and changed when needed but most changes were incremental compared to NRC 2001. The feed composition library was completely revised using improved statistical filtering techniques which should greatly increase the accuracy of the standard deviation estimates. Requirements for young calves were extensively modified based on new data. Software is included with the publication.