The Ba deoxidation of NiTi alloy melts with two different levels of initial oxygen content was investigated. Metallic Ba was added to the NiTi alloy melts held in CaO crucibles at 1673 K. The oxygen and Ba contents in the melts were quantitatively measured, and the precipitates in the NiTi alloys were analyzed, based on electrolytic extraction, after cooling in the CaO crucibles. The oxygen contents of the NiTi alloy melts decreased to 131 ppm and to 212 ppm in the NiTi alloy melts with low and high levels of initial oxygen contents, respectively, through the Ba deoxidation. The Ba content in the NiTi alloy melts was less than 10 ppm, 120 s after the addition of Ba, independent of the initial oxygen content levels. The content of the precipitates was decreased by the Ba deoxidation. The phase of the precipitates depended on the oxygen and carbon contents in the NiTi alloy melts; the Ba deoxidation changed the phase of the precipitates from Ni2Ti4O and Ti(C, N, O) types to Ti(C, N, O) and from Ni2Ti4O type to Ti(C, N, O) type for NiTi alloys with low and high levels of initial oxygen contents, respectively.