The thermal analysis of Co(NIA)(2)(H2O)(4) (NIA=nicotinate) in nitrogen has been investigated by thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA). The isoconversional method was applied to estimate the activation energy of decomposition. A comparison between the thermal process corresponding to nitrogen and air atmospheres has also been performed. (c) 2005 Elsevier B.V. All rights reserved.