Solid solubility extension of magnesium in titanium was obtained by mechanical alloying of blended elemental powders. The solubilities achieved varied with the processing variables used. A maximum solubility of 3.6 at% (1.9 wt%) magnesium in titanium (representing a 3% density decrease) was achieved when both the titanium and magnesium powders were premilled separately and then mechanically alloyed together. This compares with the equilibrium solid solubility of 0.2 at% (0.1 wt%) Mg in Ti at 500 °C. As the temperature of milling was lowered, the solubility level was reduced.