Al2O3-MgO (AM) fibres containing 98.16 wt % Al2O3 and 1.84 wt % MgO, were produced via inviscid melt spinning. By using scanning electron microscopy it was found that the as-spun AM fibres were hollow and their surfaces were very rough, The X-ray diffraction pattern of the as-spun AM fibre showed delta-Al2O3 as a major phase and alpha-Al2O3 as a minor phase. The DTA curve of the as-spun AM fibre showed a single endothermic peak representing the phase transformation of delta-Al2O3 to alpha-Al2O3. This phase transformation was readily confirmed by analysing the X-ray diffraction pattern of heat-treated AM fibres.