To establish a relationship between the secondary structure of a peptide and the quadrupolar coupling of its amide N-14, we examined N-14 quadrupolar couplings for eight different polypeptide samples, each of whose secondary structure (alpha-helix or beta-sheet) is known. The N-14 quadrupolar coupling is estimated from indirect observation of a N-14 overtone resonance under magic-angle spinning. From the observed indirect N-14 overtone spectra and calculated N-14 quadrupolar couplings for model molecules by using ab initio calculation (Gaussian03), it is shown that the quadrupolar coupling for the alpha-helix is larger than that for the beta-sheet by a few 100 kHz irrespective of the kind of amino acid residues examined (Ala, Val, Leu).