The preparation of salts or complexes of N-hydroxy urea with Na+, Li+, Mg2+, VO2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+ und Pt2+ is reported. Their i.r.-spectra and the n.m.r.-spectra of the ligand and its alkali salts as well as of the methylated and deuterated derivative are discussed. Finally lhe complex stability constants of Mn2+, Co2+, Ni2+, Cu2+ and Zn2+ compounds are measured and discussed.