A series of nuclear magnetic resonance (NMR) spectra of whole seeds of various types was obtained by using cross polarization-magic angle spinning (CP/MAS) techniques. Select signals in the spectra provided a means of comparing the protein content relative to the starch content within a group of seed varieties. Seeds obtained from legumes were found to be high in protein content, with different legumes showing a range of protein NMR signal intensities. A series of sorghum varieties and a series of grain types were also analyzed, and the protein content of these series was compared to that of the legumes and to that of one another. The potential of 13C CP/MAS NMR for the study of seeds and other intact plant materials is strongly indicated.