Novel mono- and sym. di-N-hydroxy- and N-aminoguanidines were readily prepd. from the reaction of diverse hydroxylamines or hydrazines with di(benzotriazol-1-yl)methanimine, (bis-benzotriazol-1-yl-methylene)amines, benzotriazole-1-carboxamidines, benzotriazole-1-carboximidamides, and N'-hydroxy-1H-1,2,3-benzotriazole-1-carboximidamide. The prepn. is described for a variety of N-hydroxy- and N-aminoguanidines with different substitution patterns in good yields.