Antibodies recognize their target with high affinity and specificity. This is important for pathogen neutralization, which plays a crucial role in defense against disease. Antibodies are powerful tools in the development of new therapeutics, such as vaccines, to fight diseases such as viral infections and even cancer. The development of monoclonal and specific antibodies is time-consuming and expensive, but it can be greatly simplified with structural and allosteric information. Nuclear magnetic resonance (NMR) is a powerful technique to study protein structure and dynamics, and it has proven to be efficient to analyze large protein complexes, despite the overall size limitation. Here, we discuss NMR approaches efficiently used to conformational epitope mapping.