Thermal decompositions of acetylsalicylhydroxamic acid and of the Co(II), Ni(II), Cu(II) and Zn(II) complexes has been investigated by TG, DTG and DTA. The complexes decompose to yield very stable solid intermediates at about 195°C which are characterized by IR spectroscopy, elemental analysis and magnetic moment measurements. Thermal decomposition results in the formation of the metal oxides as residues. Kinetic parameters for the dehydration and decomposition stages are also derived. © 2000 Elsevier Science B.V.