This unit aims to overview the application of NMR spectroscopy to proteins. It is not intended to provide an exhaustive "how to" guide, but rather to give a flavor of both well-established and emerging NMR techniques used in the elucidation of protein structure. It starts with a brief introduction to the basic principles of NMR and the information provided by this technique, and goes on to discuss the instrumentation involved, spectral assignment methods for small and large proteins, and the utility of other spin active nuclei (e.g., (13)C and (15)N) to aid assignment of the latter.