Synthesis, characterization and thermal behavior of some transition metal glycolates, M(C 2 H 3 O 3 ) 2 [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)], as well as the thermal behavior of glycolic acid and its sodium salt (NaC 2 H 3 O 3 ) were investigated employing simultaneous thermogravimetry and differential thermal analysis, infrared spectroscopy (FTIR), simultaneous thermogravimetrydifferential scanning calorimetry coupled to FTIR (evolved gas analysis), complexometry and high-resolution electrospray ionization mass spectrometry. The lowest energy model structure of each complex has been proposed by using the density functional theory at the B3LYP/6-311??g(d) level of theory. The results provided information concerning the composition, dehydration, thermal stability, thermal decomposition and identification of the gaseous products evolved during the thermal decomposition of these compounds in dynamic dry air atmosphere.