β titanium alloys have been widely used as implantation inside the human body. Based on this, two β Ti-based medium entropy alloys (namely; Ti45Zr33Nb22 and Ti40Zr33Nb22Mn5, at. %) were designed using mean bond order (Bo) and mean d-orbital energy level (Md) diagram along with the CALPHAD approaches. The two alloys showed single β phase composed of a dendritic structure. When 5 at. % of Ti was replaced by Mn in Ti45Zr33Nb22alloy, the compressive yield strength has increased. Furthermore, the hardness was increased upon the addition of Mn. Finally, Ti45Zr33Nb22alloy showed good cold workability and slight hardness increase upon cold rolling up to 90% reduction.