The availability of a series of ethene/4-methyl-1-pentene copolymers spreading over a very broad range of chemical compositions, from about 1% up to 90% as 4-methyl-l-pentene molar content, paralleled by the heteronuclear H-1- C-13 gradient-assisted 2D NMR techniques, has allowed for an improved peak assignment of their C-13 NMR spectra. In particular, sequences richer in comonomer could be assigned, and the previous ambiguous assignment of S alpha gamma methylene carbon of the main chain was corrected. Starting from whole set of the previous and newly proposed assignments, a comprehensive check of consistency of the C-13 NMR assignment can be completely fulfilled. From now on, the correct evaluation of the copolymer microstructure at tetrad level and of the copolymerization parameters of this interesting family of copolymers will be accessible.