CaO-Al2O3-MgO (CAM) ceramic fibre produced via inviscid melt spinning (IMS) was investigated for phase transformation. Differential thermal analysis (DTA) on the as-spun CAM fibre gave two transformation peaks, one for exothermic peak at around 927 degrees C and the other for endothermic one at around 1100 degrees C. In order to identify each phase transformation x-ray diffraction (XRD) analysis was performed on the CAM fibres heat-treated to each phase transformation completion temperature. The exothermic peak was determined to represent crystallization of remaining amorphous phase in the as-spun CAM fibre. The endothermic peak was determined to correspond to transformation of non-equilibrium CaO . Al2O3 phase to equilibrium 3CaO . 5Al(2)O(3) phase.