The paper describes computer analysis of concentration dependence of oxygen activity coefficients f(o) in binary liquid titanium-base alloys containing ions of copper, nickel, molybdenum, vanadium, zirconium and aluminum. The study covers calculations of oxygen activity coefficient f(o) and sulphur activity coefficient f(s) in binary melts of the systems Cu - Fe, Cu - Ni, Cu - Co, Ni - Co, Fe - Ni, Fe - Co as a function of the concentration of metal components.