Summary Red mud is insoluble, fine-grained waste residue which is generated as a by product during the production of alumina from the Bayer process. In this article, the thermal behavior of Aughinish red mud was investigated using thermal gravimetric analysis (TG) and differential thermal analysis (DTA). For identification of oxide and mineral phases in the red mud sample, XRD method, scanning electron microscopy (SEM), EDAX were used. Iron (30.4%), aluminium (23.6%) and titanium (17.85%) oxides are major oxides in the sample. Two endothermic peaks were shown on DTA curve. The total mass loss in the red mud was found to be 10.1%, which was associated with moisture and water molecules in gibbsite and boehmite phases.