The microstructure of ethene/norbornene copolymers produced by metallocene/methylaluminoxane catalysts is investigated by C-13 NMR spectroscopy. The microstructure of alternating copolymers is assigned on the pentad level by comparison of the pentad distribution in C-13 NMR spectra with the calculated distribution according to the alternating mechanism. Norbornene block structures produced with different catalysts are compared, and norbornene diblock structures are assigned. Triad distributions for the alternating copolymers and diad distributions for copolymers containing diblocks were obtained.