This article describes the complete vibrational analysis of N,N'-dimethyloxamide, CH 3 HNCOCONHCH 3 , on basis of the infrared and Raman spectra of four isotopes (H, D, CH 3 , CD 3 ). Force field calculations on the monomers and multimers (n=5) combined with solid state spectra in the -196 to +100 o C temperature range have been used to obtain a better understanding of the influence of hydrogen bonding on the typical amide fundamentals. The cooperative effect in de series monomer->multimers->solid state at decreasing temperatures has been demonstrated. Nine typical so-called 'amide bands' have been further characterized and special attention has been given to the Amide IV mode.The influence of the CH and CD vibrations on the amide fundamentals, has been studied by comparison with the calculated and experimental fundamentals and P.E.D. values of the CH 3 and CD 3 isotopes. The most important amide bands have further been assigned in X-CONHCH 3 molecules where X=methyl, amide, thioamide, ester, salt, cyanide and acid functional groups.