The simple neutral diazenium diolate, O-2-methyl-1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate, [Me2NN(O)= NOMe], was experimentally examined by vibrational spectroscopy and the results compared to the theoretically calculated values in an effort to detect both Z and E conformers which result from the stereochemistry of the N=N multiple bond. Room-temperature Raman and infrared spectra were measured and the results compared with the values calculated theoretically with MP2 and density functional techniques (B3LYP). An analysis of the observed frequencies suggests that, down to a detection limit of about (1)/(1000), only a small quantity of trans (E) diazeniumdiolate, < 0.05%, may be present at room temperature.