The differential thermal analysis-thermogravimetry (DTA-TG) behaviour of chemically coprecipitated iron(III) oxalate-magnesium oxalate (1 : 1 mole ratio) was investigated. X-ray diffractometry (XRD) of samples calcined at different temperatures showed that magnesium ferrite is formed in samples heated at higher temperatures. Integral composite analyses of dynamic TG data of the decomposition reactions in the coprecipitated mixture were carried out using various solid state reaction model equations, and the results showed that the decomposition reactions are best described by the two- and three-phase boundary, R(2) and R(3) models. Kinetic analyses of dynamic data were also carried out in accordance with the integral methods of Ozawa and Coats-Redfern and the results are discussed in comparison with the integral composite analysis of data.