Investigation of large nucleic acids (> 30 kDa) challenges the current limits of NMR spectroscopy. Extended helical regions in RNA and DNA increase correlation times more so than for proteins of comparable size, resulting in line broadening and reduced sensitivity. Also, the lower proton density and poor proton spectral dispersion in nucleic acids can reduce the effectiveness of traditional solution NMR methods in studies of large nucleic acids. These limitations represent a substantial hindrance to the future investigation of biologically relevant large nucleic acid structures. Herein we describe methods that have been implemented to help overcome these challenges and extend the size limits of nucleic acid NMR spectroscopy, including construct design, selective isotopic labeling, multi-dimensional NMR experiments and complementary techniques.