Abstract The IR and NMR spectra of the tosylate salts of 12 new N-hydroxyguanidine derivatives are compiled. The various IR absorption peaks in KBr pellets and the chemical shifts of the aldehyde moiety of the Schiff bases of N-hydroxy-N'-aminoguanidine and the N-hydroxy-N'-aminoguanidine group of these compounds in dimethyl sulfoxide are reported.