Spherical Ti-28Ta (at.%) or Ti-60Ta (wt.%) alloy powder was produced by the plasma rotating electrode process (PREP). The PREP Ti-28Ta alloy particles showed highly smooth surfaces and contained no ‘satellite’ particles. The flowability of the powder reached 15.5s/50g. The microstructure of the powder particles was dependent on particle size. Martensitic α''-phase was found to be predominant in the small particles (40-65μm), accompanied by retained β-phase and a trace amount of athermal ω-phase. In contrast, the predominant phase in large particles (150-178μm) was found to be retained β-phase together with martensitic α''-phase and a trace amount of athermal ω-phase. The martensitic α''-phase preferentially formed along the β grain boundaries in the PREP Ti-28Ta powder.