Following recent work on creatinine complexes of copper(II), creatinine complexes of nickel(II) with various anions have been prepared for the first time and characterised by elemental analysis, solid state infrared spectroscopy and thermal analysis methods. Analysis of the gases evolved during thermal analysis with a coupled FTIR spectrometer provided support for the proposed decomposition sequence. In the case of the complex chloride, [Ni(creat)(2)(H2O)(2)]Cl-2 the loss of coordinated water has been shown to be reversible.